Multilayer ceramic electronic component

ABSTRACT

A multilayer ceramic capacitor includes an external electrode including an underlying electrode layer, a lower plating layer on the underlying electrode layer at a first end surface and a second end surface, and an upper plating layer on the lower plating layer. The underlying electrode layer is a thin film electrode including at least one selected from Ni, Cr, Cu, and Ti. The lower plating layer is a Cu plating layer including a lower layer region located closer to the multilayer body and an upper layer region located between the lower layer region and the upper plating layer, and the Cu plating layer in the lower layer region has a metal grain diameter smaller than that of the Cu plating layer located in the upper layer region.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2020-074660 filed on Apr. 20, 2020. The entire contentsof this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a multilayer ceramic electroniccomponent, and more particularly, to a multilayer ceramic electroniccomponent including an external electrode with a multilayer structure.

2. Description of the Related Art

In recent years, electronic devices such as mobile phones and portablemusic players are increasingly reduced in size and thickness. Along withthis, multilayer ceramic electronic components mounted in suchelectronic devices are also increasingly reduced in size and thickness.

A multilayer ceramic capacitor that is an example of such a multilayerceramic electronic component includes, for example, a ceramic sinteredbody in which a dielectric ceramic material, such as barium titanate,and an internal electrode are alternately stacked, and a pair ofexternal electrodes formed so as to cover each end surface of theceramic sintered body (see Japanese Patent Laid-Open No. 8-306580).

As one method for achieving miniaturization and large capacitance, thereis a technique of forming an external electrode as a plating electrode(Cu plating), as disclosed in Japanese Patent Laid-Open No. 2009-283597,for example. Japanese Patent Laid-Open No. 8-306580 discloses that aplating electrode (Cu plating) can be formed directly on the body of anelectronic component to reduce the external electrode in thickness, andas the external electrode is reduced in thickness, the ceramic body canbe formed as large as possible within a standard dimension to increasethe internal electrode's effective area.

However, it is known that when a plating electrode (Cu plating) isformed on a ceramic body, as described in Japanese Patent Laid-Open No.2009-283597, it insufficiently adheres to a ceramic multilayer body, theinternal electrode and the like, and external moisture intrudes andmoisture resistance is degraded.

Accordingly, to solve this problem, forming the plating electrode (Cuplating) may be followed by performing heat treatment to increase thegrain size of the metal included in the plating electrode to increase anarea brought into contact with the ceramic body to ensure that theelectrode adheres to the ceramic multilayer body.

However, applying heat treatment to increase the grain size of the metalincluded in the plating electrode (Cu plating) increases compressivestress of the grains, and thus compressive stress of the platingelectrode (Cu plating). The external electrode is formed on a firstmajor surface and a second major surface, a first side surface and asecond side surface, and a first end surface and a second end surface,and accordingly, a tensile stress is generated at a peripheral portionof the plating electrode (Cu plating) formed on the first and secondmajor surfaces and the first and second side surfaces. When thermalstress (for example, ΔT of 230° C. in solder reflow mounting, and ΔT of140° C. or higher and 180° C. or lower for thermal shock of a productafter mounting) is applied in this state, a tensile force isconcentrated at the peripheral portion of the plating electrode (Cuplating). Therefore, a force in a vertical direction, which is adirection of a stress by which the external electrode is tensioned withrespect to the ceramic body, is applied to the peripheral portion of theplating electrode (Cu plating), and the ceramic body may be cracked bythermal stress. This problem is prominent as the ceramic body becomessmaller in thickness.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide multilayerceramic electronic components that are each capable of reducing orpreventing cracking of a multilayer body due to thermal stress duringreflow mounting or the like.

According to a preferred embodiment of the present invention, amultilayer ceramic electronic component includes a multilayer bodyincluding a plurality of stacked ceramic layers and including a firstmajor surface and a second major surface opposite to each other in aheight direction, a first side surface and a second side surfaceopposite to each other in a width direction orthogonal or substantiallyorthogonal to the height direction, and a first end surface and a secondend surface opposite to each other in a length direction orthogonal orsubstantially orthogonal to the height direction and the widthdirection; a first internal electrode layer on the ceramic layer andexposed at the first end surface; a second internal electrode layer onthe ceramic layer and exposed at the second end surface; a firstexternal electrode on the first end surface and connected to the firstinternal electrode layer; and a second external electrode on the secondend surface and connected to the second internal electrode layer, thefirst and second external electrodes including an underlying electrodelayer, a lower plating layer on the underlying electrode layer at thefirst end surface and the second end surface, respectively, and an upperplating layer on the lower plating layer, the underlying electrode layerbeing a thin film electrode including at least of Ni, Cr, Cu, or Ti, thelower plating layer being a Cu plating layer, the lower plating layerincluding a lower layer region located closer to the multilayer body andan upper layer region located between the lower layer region and theupper plating layer, the Cu plating layer located in the lower layerregion having a metal grain diameter smaller than that of the Cu platinglayer located in the upper layer region.

With the multilayer ceramic electronic component according to apreferred embodiment of the present invention, the first and secondexternal electrodes include an underlying electrode layer, a lowerplating layer on the underlying electrode layer at the first end surfaceand the second end surface, respectively, and an upper plating layer onthe lower plating layer, the underlying electrode layer is a thin filmelectrode including at least one of Ni, Cr, Cu, or Ti, the lower platinglayer is defined by a Cu plating layer, the lower plating layer includesa lower layer region located closer to the multilayer body and an upperlayer region located between the lower layer region and the upperplating layer, and the Cu plating layer located in the lower layerregion has a metal grain diameter smaller than that of the Cu platinglayer located in the upper layer region, so that a multilayer ceramicelectronic component according to a preferred embodiment of the presentinvention each ensure adhesion with the multilayer body by theunderlying electrode layer defined by the thin film layer, and canreduce compressive stress throughout the lower plating layer as thelower layer region includes metal grains having a smaller graindiameter. As a result, even when thermal stress is applied, tensilestress applied to a peripheral portion of the lower plating layer isable to be reduced or prevented, and cracking of the multilayer body dueto the thermal stress is able to be reduced or prevented.

Further, a multilayer ceramic electronic component according to apreferred embodiment of the present invention that includes a lowerplating layer including an upper layer region including metal grainshaving a larger grain diameter than that of metal grains of a lowerlayer region of the lower plating layer ensures that the lower platinglayer is thick, and are able to reduce or prevent penetration of themultilayer body by moisture. As a result, reduction or prevention ofdegradation of reliability in resistance to moisture is achieved.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective view of a multilayer ceramic capacitoras an example of a multilayer ceramic electronic component according toa first preferred embodiment of the present invention.

FIG. 2 is a front view of the multilayer ceramic capacitor as theexample of the multilayer ceramic electronic component according to thefirst preferred embodiment of the present invention.

FIG. 3 is a top view of the multilayer ceramic capacitor as the exampleof the multilayer ceramic electronic component according to the firstpreferred embodiment of the present invention.

FIG. 4 is a cross section taken along a line IV-IV indicated in FIG. 1.

FIG. 5 is a cross section taken along a line V-V indicated in FIG. 1.

FIG. 6 is a schematic cross section for illustrating a structure of anexternal electrode according to a preferred embodiment of the presentinvention.

FIG. 7 is a cross section taken along a line VII-VII indicated in FIG.1.

FIG. 8 is an external perspective view of a multilayer ceramic capacitoras an example of a multilayer ceramic electronic component according toa first exemplary variation of the first preferred embodiment of thepresent invention.

FIG. 9 is a front view of the multilayer ceramic capacitor as theexample of the multilayer ceramic electronic component according to thefirst exemplary variation of the first preferred embodiment of thepresent invention.

FIG. 10 is a top view of the multilayer ceramic capacitor as the exampleof the multilayer ceramic electronic component according to the firstexemplary variation of the first preferred embodiment of the presentinvention.

FIG. 11 is a cross section taken along a line XI-XI indicated in FIG. 1.

FIG. 12 is a cross section taken along a line XII-XII indicated in FIG.1.

FIG. 13 is a cross section taken along a line XIII-XIII indicated inFIG. 1.

FIG. 14 is a central front cross section of a multilayer ceramiccapacitor as an example of a multilayer ceramic electronic componentaccording to a second exemplary variation of the first preferredembodiment of the present invention.

FIG. 15 is a central front cross section of a multilayer ceramiccapacitor as an example of a multilayer ceramic electronic componentaccording to a third exemplary variation of the first preferredembodiment of the present invention.

FIG. 16 is an external perspective view of a multilayer ceramiccapacitor as an example of a multilayer ceramic electronic componentaccording to a second preferred embodiment of the present invention.

FIG. 17 is a cross section taken along a line XVII-XVII indicated inFIG. 16.

FIG. 18 is a cross section taken along a line XVIII-XVIII indicated inFIG. 16.

FIG. 19 is a cross section taken along a line XIX-XIX indicated in FIG.16.

FIG. 20 is an exploded perspective view of a multilayer body shown inFIG. 16.

FIG. 21A shows a first internal electrode pattern of the multilayerceramic capacitor shown in FIG. 16.

FIG. 21B shows a second internal electrode pattern of the multilayerceramic capacitor shown in FIG. 16.

FIG. 22 is a schematic cross section for illustrating a structure of anexternal electrode according to a preferred embodiment of the presentinvention.

FIG. 23 is a schematic cross section for illustrating a structure of anexternal electrode according to a preferred embodiment of the presentinvention.

FIG. 24A is an external perspective view of a multilayer ceramiccapacitor as an example of a multilayer ceramic electronic componentaccording to an exemplary variation of the second preferred embodimentof the present invention.

FIG. 24B is a bottom view of the multilayer ceramic capacitor as theexample of the multilayer ceramic electronic component according to theexemplary variation of the second preferred embodiment of the presentinvention.

FIG. 25 is an external perspective view of a multilayer body of themultilayer ceramic capacitor shown in FIG. 16.

FIG. 26 is an external perspective view in which an underlying electrodelayer is provided on the multilayer body shown in FIG. 25.

FIG. 27 is an external perspective view in which a plating layer isprovided on the multilayer body shown in FIG. 26.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, multilayer ceramic electronic components according topreferred embodiments of the present invention will be described belowwith reference to the drawings.

A. First Preferred Embodiment 1. Multilayer Ceramic Capacitor

A multilayer ceramic capacitor 10 which is an example of a multilayerceramic electronic component according to a first preferred embodimentof the present invention will be described. FIG. 1 is an externalperspective view of a multilayer ceramic capacitor as an example of amultilayer ceramic electronic component according to the first preferredembodiment of the present invention. FIG. 2 is a front view of themultilayer ceramic capacitor as the example of the multilayer ceramicelectronic component according to the first preferred embodiment of thepresent invention. FIG. 3 is a top view of the multilayer ceramiccapacitor as the example of the multilayer ceramic electronic componentaccording to the first preferred embodiment of the present invention.FIG. 4 is a cross section taken along a line IV-IV indicated in FIG. 1.FIG. 5 is a cross section taken along a line V-V indicated in FIG. 1.FIG. 6 is a schematic cross section for illustrating a structure of anexternal electrode according to the present invention. FIG. 7 is a crosssection taken along a line VII-VII indicated in FIG. 1.

Multilayer ceramic capacitor 10 includes a multilayer body 12 and anexternal electrode 24. Hereinafter, multilayer body 12 and externalelectrode 24 will each be described.

Multilayer body 12 includes a plurality of ceramic layers 14 and aplurality of internal electrode layers 16 that are stacked in layers.Further, multilayer body 12 includes a first major surface 12 a and asecond major surface 12 b opposite to each other in a height directionx, a first side surface 12 c and a second side surface 12 d opposite toeach other in a width direction y orthogonal or substantially orthogonalto height direction x, and a first end surface 12 e and a second endsurface 12 f opposite to each other in a length direction z orthogonalor substantially orthogonal to height direction x and width direction y.Multilayer body 12 has rounded corners and ridges. A corner is a portionwhere three adjacent surfaces of multilayer body 12 meet one another,and a ridge is a portion where two adjacent surfaces of multilayer body12 meet each other. Further, some or all of first and second majorsurfaces 12 a and 12 b, first and second side surfaces 12 c and 12 d,and first and second end surfaces 12 e and 12 f may include a recess anda projection or the like, for example.

As shown in FIGS. 4 and 5, in height direction x connecting first majorsurface 12 a and second major surface 12 b, multilayer body 12 includesan effective layer portion 15 a in which a plurality of internalelectrode layers 16 are opposite to one another, a first outer layerportion 15 b 1 including a plurality of ceramic layers 14 locatedbetween an internal electrode layer 16 located closest to first majorsurface 12 a and first major surface 12 a, and a second outer layerportion 15 b 2 including a plurality of ceramic layers 14 locatedbetween an internal electrode layer 16 located closest to second majorsurface 12 b and second major surface 12 b.

First outer layer portion 15 b 1 includes a plurality of ceramic layers14 located on a side of multilayer body 12 closer to first major surface12 a between first major surface 12 a and internal electrode layer 16closest to first major surface 12 a.

Second outer layer portion 15 b 2 includes a plurality of ceramic layers14 located on a side of multilayer body 12 closer to second majorsurface 12 b between second major surface 12 b and internal electrodelayer 16 closest to second major surface 12 b.

A region sandwiched between first outer layer portion 15 b 1 and secondouter layer portion 15 b 2 is effective layer portion 15 a. While thenumber of ceramic layers 14 that are stacked is not particularlylimited, preferably, for example, 15 or more and 70 or less ceramiclayers 14 are stacked including first outer layer portion 15 b 1 andsecond outer layer portion 15 b 2. Ceramic layer 14 preferably has athickness of about 0.4 μm or more and about 10 μm or less, for example.

Ceramic layer 14 can be made of, for example, a dielectric material. Thedielectric material can, for example, be a dielectric ceramic materialincluding BaTiO₃, CaTiO₃, SrTiO₃, CaZnO₃ or the like as a maincomponent. Further, the material may include these as a main componentand an Mn compound, an Fe compound, a Cr compound, a Co compound, a Nicompound or the like added thereto as a sub-component.

While multilayer body 12 is not particularly limited in dimension, itpreferably has, for example, a dimension of about 0.2 mm or more andabout 10 mm or less in length direction z, a dimension of about 0.1 mmor more and about 10 mm or less in width direction y, and a dimension ofabout 30 μm or more and about 200 μm or less in height direction x. Inparticular, the present preferred embodiment is more effective formultilayer body 12 having a small dimension in height direction x. Thisis because multilayer body 12 having a smaller dimension in heightdirection x is reduced in mechanical strength.

As shown in FIGS. 4 and 5, internal electrode layer 16 includes a firstinternal electrode layer 16 a and a second internal electrode layer 16b. First internal electrode layer 16 a and second internal electrodelayer 16 b are alternately stacked with ceramic layer 14 interposed.

First internal electrode layer 16 a is disposed on a surface of ceramiclayer 14. First internal electrode layer 16 a includes a first oppositeelectrode portion 18 a opposite to second internal electrode layer 16 b,and a first lead electrode portion 20 a located on the side of one endof first internal electrode layer 16 a and extending from first oppositeelectrode portion 18 a to first end surface 12 e of multilayer body 12.First lead electrode portion 20 a includes an end thereof extending tofirst end surface 12 e and thus exposed.

While first opposite electrode portion 18 a of first internal electrodelayer 16 a is not particularly limited in shape, it is preferablyrectangular or substantially rectangular in plan view. However, it mayhave a rounded corner, be provided obliquely in plan view (or tapered),or the like, for example. Alternatively, for example, it may be taperedin plan view such that it is inclined toward either side.

While first lead electrode portion 20 a of first internal electrodelayer 16 a is not particularly limited in shape, it is preferablyrectangular or substantially rectangular in plan view. However, it mayhave a rounded corner, be provided obliquely in plan view (or tapered),or the like, for example. Alternatively, for example, it may be taperedin plan view such that it is inclined toward either side.

First opposite electrode portion 18 a of first internal electrode layer16 a and first lead electrode portion 20 a of first internal electrodelayer 16 a may have an equal or substantially equal width, or one ofthem may have a smaller width than the other.

Second internal electrode layer 16 b is disposed on a surface of ceramiclayer 14 different from ceramic layer 14 on which first internalelectrode layer 16 a is disposed. Second internal electrode layer 16 bincludes a second opposite electrode portion 18 b opposite to firstinternal electrode layer 16 a, and a second lead electrode portion 20 blocated on the side of one end of second internal electrode layer 16 band extending from second opposite electrode portion 18 b to second endsurface 12 f of multilayer body 12. Second lead electrode portion 20 bincludes an end thereof extending to second end surface 12 f and thusexposed.

While second opposite electrode portion 18 b of second internalelectrode layer 16 b is not particularly limited in shape, it ispreferably rectangular or substantially rectangular in plan view.However, it may have a rounded corner, be provided obliquely in planview (or tapered), or the like, for example. Alternatively, for example,it may be tapered in plan view such that it is inclined toward eitherside.

While second lead electrode portion 20 b of second internal electrodelayer 16 b is not particularly limited in shape, it is preferablyrectangular or substantially rectangular in plan view. However, it mayhave a rounded corner, be provided obliquely in plan view (or tapered),or the like. Alternatively, it may be tapered in plan view such that itis inclined toward either side.

Second opposite electrode layer 18 b of second internal electrode layer16 b and second lead electrode portion 20 b of second internal electrodelayer 16 b may have an equal or substantially equal width, or one ofthem may have a smaller width than the other.

Further, as shown in FIG. 4, multilayer body 12 includes an end portion22 b (hereinafter referred to as an “L gap”) of multilayer body 12between an end portion of first internal electrode layer 16 a oppositeto first lead electrode portion 20 a and second end surface 12 f, andbetween an end portion of second internal electrode layer 16 b oppositeto second lead electrode portion 20 b and first end surface 12 e.

As shown in FIG. 5, multilayer body 12 includes a side portion(hereinafter referred to as a “W gap”) 22 a of multilayer body 12between one end of each of first and second opposite electrode portions18 a and 18 b in width direction y and first side surface 12 c, andbetween the other end of each of first and second opposite electrodeportions 18 a and 18 b in width direction y and second side surface 12d.

First internal electrode layer 16 a and second internal electrode layer16 b can be made, for example, of an appropriate conductive material,such as a metal such as for example Ni, Cu, Ag, Pd or Au, or an alloyincluding at least one of these metals, such as an Ag—Pd alloy. Internalelectrode layer 16 may further include dielectric grains having the sameor substantially the same composition as a ceramic material included inceramic layer 14.

When a piezoelectric ceramic material is used for multilayer body 12,the multilayer ceramic electronic component defines and functions as aceramic piezoelectric element 10 a. Specific examples of thepiezoelectric ceramic material include a PZT (lead zirconate titanate)based ceramic material and the like.

When a semiconducting ceramic material is used for multilayer body 12,the multilayer ceramic electronic component defines and functions as athermistor element 10 b. Specific examples of the semiconducting ceramicmaterial include a spinel ceramic material and the like.

When a magnetic ceramic material is used for multilayer body 12, themultilayer ceramic electronic component defines and functions as aninductor element 10 c. When the multilayer ceramic electronic componentdefines and functions as the inductor element, the internal electrodelayer will be a coil-shaped conductor. Specific examples of the magneticceramic material include, for example, a 0 material or the like.

That is, the multilayer ceramic electronic component according to thepresent preferred embodiment can defines and function suitably not onlyas multilayer ceramic capacitor 10, but also as ceramic piezoelectricelement 10 a, thermistor element 10 b, or inductor element 10 c byappropriately changing multilayer body 12 in material and structure.

Internal electrode layer 16, that is, first internal electrode layer 16a and second internal electrode layer 16 b, preferably has a thicknessof about 0.2 μm or more and about 2.0 μm or less, for example. A totalnumber of first and second internal electrode layers 16 a and 16 b ispreferably 15 or more and 200 or less layers, for example.

While internal electrode layer 16 may be parallel or substantiallyparallel to a surface to be mounted on a mounting substrate, or may beperpendicular or substantially perpendicular thereto, it is morepreferable that internal electrode layer 16 are parallel orsubstantially parallel thereto.

As shown in FIGS. 1 to 4, external electrode 24 is disposed on the sideof first end surface 12 e of multilayer body 12 and on the side ofsecond end surface 12 f of multilayer body 12.

External electrode 24 includes an underlying electrode layer 26 and aplating layer 28 covering underlying electrode layer 26.

External electrode 24 includes a first external electrode 24 a and asecond external electrode 24 b.

First external electrode 24 a is disposed on multilayer body 12 only ata surface of first end surface 12 e, a portion of first major surface 12a, and a portion of second major surface 12 b. In this case, firstexternal electrode 24 a is electrically connected to first leadelectrode portion 20 a of first internal electrode layer 16 a. Further,first external electrode 24 a is not disposed on a portion of first sidesurface 12 c and a portion of second side surface 12 d.

Second external electrode 24 b is disposed on multilayer body 12 only ata surface of second end surface 12 f, a portion of first major surface12 a, and a portion of second major surface 12 b. In this case, secondexternal electrode 24 b is electrically connected to second leadelectrode portion 20 b of second internal electrode layer 16 b. Further,second external electrode 24 b is not disposed on a portion of firstside surface 12 c and a portion of second side surface 12 d.

In multilayer body 12, first opposite electrode portion 18 a of firstinternal electrode layer 16 a and second opposite electrode portion 18 bof second internal electrode layer 16 b are opposite to each other withceramic layer 14 interposed to generate a capacitance. Therefore,capacitance can be obtained between first external electrode 24 a towhich first internal electrode layer 16 a is connected and secondexternal electrode 24 b to which second internal electrode layer 16 b isconnected, and a capacitor's characteristics are obtained.

Underlying electrode layer 26 includes a first underlying electrodelayer 26 a 1, a second underlying electrode layer 26 a 2, a thirdunderlying electrode layer 26 b 1, and a fourth underlying electrodelayer 26 b 2. First underlying electrode layer 26 a 1, second underlyingelectrode layer 26 a 2, third underlying electrode layer 26 b 1, andfourth underlying electrode layer 26 b 2 are defined by a thin filmlayer including a plurality of thin film electrodes to further improveperformance.

First underlying electrode layer 26 a 1 covers multilayer body 12 at aportion of first major surface 12 a on the side of first end surface 12e. Second underlying electrode layer 26 a 2 covers multilayer body 12 ata portion of second major surface 12 b on the side of first end surface12 e.

Third underlying electrode layer 26 b 1 covers multilayer body 12 at aportion of first major surface 12 a on the side of second end surface 12f. Fourth underlying electrode layer 26 b 2 covers multilayer body 12 ata portion of second major surface 12 b on the side of second end surface12 f.

Underlying electrode layer 26 defined by the thin film layer ispreferably formed in a thin film formation method, such as sputtering orvapor deposition, for example. In particular, underlying electrode layer26 defined by the thin film layer is preferably a sputtered electrodeformed by sputtering. Hereinafter, an electrode formed by sputteringwill be described.

When underlying electrode layer 26 is formed by a sputtered electrode,it is preferable to form the sputtered electrode directly on multilayerbody 12 at a portion of first major surface 12 a and a portion of secondmajor surface 12 b.

Underlying electrode layer 26 including the sputtered electrodepreferably includes at least one selected from Ni, Cr, Cu, Ti, and thelike, for example.

In height direction x connecting first major surface 12 a and secondmajor surface 12 b, the sputtered electrode preferably has a thicknessof, for example, about 50 nm or more and about 400 nm or less, and morepreferably about 50 nm or more and about 130 nm or less.

Plating layer 28 includes a first plating layer 28 a and a secondplating layer 28 b. First plating layer 28 a covers first underlyingelectrode layer 26 a 1 and second underlying electrode layer 26 a 2.Second plating layer 28 b covers third underlying electrode layer 26 b 1and fourth underlying electrode layer 26 b 2.

Plating layer 28 may include a plurality of layers. Preferably, platinglayer 28 includes a lower plating layer 30 covering underlying electrodelayer 26, and an upper plating layer 32 covering lower plating layer 30.Of plating layer 28, upper plating layer 32 preferably includes, forexample, at least one of Ni, Sn, Cu, Ag, Pd, Ag—Pd alloy, Au, and thelike.

Lower plating layer 30 includes a first lower plating layer 30 a and asecond lower plating layer 30 b. Lower plating layer 30 is disposed onunderlying electrode layer 26 at first end surface 12 e and second endsurface 12 f.

First lower plating layer 30 a is disposed on multilayer body 12 atfirst end surface 12 e free of the underlying electrode layer, andfurther covers first underlying electrode layer 26 a 1 disposed on firstmajor surface 12 a and second underlying electrode layer 26 a 2 disposedon second major surface 12 b.

Second lower plating layer 30 b is disposed on multilayer body 12 atsecond end surface 12 f free of the underlying electrode layer, andfurther covers third underlying electrode layer 26 b 1 disposed onsecond major surface 12 b and fourth underlying electrode layer 26 b 2disposed on second major surface 12 b.

This allows a second plating layer (i.e., upper plating layer 32) tohave a uniform or substantially uniform thickness and can thuseffectively reduce or prevent variation in thickness of the secondplating layer (i.e., upper plating layer 32) et. seq.

In the present preferred embodiment, lower plating layer 30 preferablyincludes metal of Cu, for example. Accordingly, lower plating layer 30is a Cu plating layer. Lower plating layer 30 is preferably, forexample, a Cu plating layer and covers a surface of underlying electrodelayer 26 to effectively reduce or prevent penetration by a platingsolution.

Further, as shown in FIG. 6, lower plating layer 30 includes a lowerlayer region 40 located on the side of multilayer body 12 and an upperlayer region 42 located between lower layer region 40 and upper platinglayer 32. Further, metal grains of a Cu plating layer located in lowerlayer region 40 have a smaller grain diameter than that of metal grainsof a Cu plating layer located in upper layer region 42. Note that agrain diameter of metal grains of a Cu plating layer means a maximumgrain diameter of the Cu plating layer in the direction of the thicknessthereof.

Lower plating layer 30 including lower layer region 40 including metalgrains having a reduced grain diameter can have a reduced compressivestress as a whole. As a result, even when thermal stress is applied,tensile stress applied to a peripheral portion of lower plating layer 30can be reduced or prevented, and cracking of multilayer body 12 due tothe thermal stress can be reduced or prevented. Further, lower platinglayer 30 including upper layer region 42 that includes metal grainshaving a larger grain diameter than that of metal grains of lower layerregion 40 is ensured to be thick and can reduce or prevent penetrationof multilayer body 12 by moisture. As a result, satisfactorily reliableresistance to moisture can be maintained while stress caused byapplication of thermal stress is reduced. Note that while in upper layerregion 42 of lower plating layer 30 tensile stress due to thermal stressmay be generated since upper layer region 42 includes metal grainshaving a large grain diameter, lower layer region 40 that includes metalgrains having a small diameter define and function as a barrier layer,and can reduce or prevent cracking due to stress caused in upper layerregion 42.

The grain diameter of the metal grains of the Cu plating layer locatedin lower layer region 40 of lower plating layer 30 and the graindiameter of the metal grains of the Cu plating layer located in upperlayer region 42 of lower plating layer 30 can be measured with thefollowing method. That is, the grain diameter of the metal grains of theCu plating layer located in lower layer region 40 of lower plating layer30 and the grain diameter of the metal grains of the Cu plating layerlocated in upper layer region 42 of lower plating layer 30 are measuredby exposing an LT cross section of multilayer ceramic capacitor 10 at a½ W position and observing a cross section of lower plating layer 30with an electron microscope. The cross section is observed preferablywith a magnification of about 20,000 times or more, for example. Tenlines are drawn in an observation plane, that is, the cross section oflower plating layer 30, at equal or substantially equal intervals in thedirection of the thickness and metal grains on the lines have theirmaximum grain diameters measured and averaged as the grain diameter ofthe grains.

Lower layer region 40 of lower plating layer 30 preferably has a smallerthickness than upper layer region 42 of lower plating layer 30. This canreduce compressive stress caused in lower plating layer 30 byapplication of thermal cycle with respect to multilayer body 12, andeffectively reduce or prevent cracking with respect to multilayer body12 due to the compressive stress.

Lower layer region 40 of lower plating layer 30 preferably has athickness of, for example, about 0.2 μm or more and about 1.0 μm orless. When lower layer region 40 of lower plating layer 30 has athickness smaller than about 0.2 μm, lower layer region 40 formed by Cuplating will be discontinuous, and for example, multilayer ceramiccapacitor 10 may not be reliably moisture-resistant. In contrast, whenlower layer region 40 of lower plating layer 30 has a thickness largerthan about 1.0 μm, the external electrode may include an end portionthat is formed unsatisfactorily as plating is grown.

Upper layer region 42 of lower plating layer 30 preferably has athickness of about 4.0 μm or more and about 8.0 μm or less, for example.When upper layer region 42 of lower plating layer 30 has a thicknesssmaller than about 4.0 μm, upper layer region 42 formed by Cu platingwill be discontinuous, and for example, multilayer ceramic capacitor 10may not be reliably moisture-resistant. In contrast, when upper layerregion 42 of lower plating layer 30 has a thickness larger than about8.0 μm, the elemental body has a thickness reduced by the amount of thethickness of the plating, and capacitance, strength and the like may notbe provided as desired.

Lower layer region 40 of lower plating layer 30 preferably includesmetal grains having a grain diameter of about 0.20 μm or less, and upperlayer region 42 of lower plating layer 30 preferably includes metalgrains having a grain diameter of about 0.50 μm or more, for example.Thus, a stress relaxation effect of lower layer region 40 of lowerplating layer 30 can reduce compressive stress caused by application ofthermal stress with respect to multilayer body 12, and effectivelyreduce or prevent cracking with respect to multilayer body 12 due to thecompressive stress. Further, with the metal grains of upper layer region42 of lower plating layer 30, an effect is obtained to reduce or preventunsatisfactory formation of an end portion of the external electrode dueto growth of plating. This is because ensuring that lower layer region40 of lower plating layer 30 is continuous requires providing athickness of an extent, and in forming a prescribed thickness, using abath allowing metal grains to be formed with a small grain diameterfacilitates growth of plating. When lower layer region 40 of lowerplating layer 30 includes metal grains having a grain diameter largerthan about 0.20 μm, compressive stress with respect to multilayer body12 by application of thermal stress increases, and cracking with respectto multilayer body 12 due to the compression stress may occur. Incontrast, when upper layer region 42 of lower plating layer 30 includesmetal grains having a grain diameter smaller than about 0.5 μm, upperlayer region 42 will be discontinuous, and for example, multilayerceramic capacitor 10 may not be reliably moisture-resistant.

Upper plating layer 32 includes a first upper plating layer 32 a and asecond upper plating layer 32 b.

First upper plating layer 32 a covers first lower plating layer 30 a.Specifically, first upper plating layer 32 a is preferably disposed on asurface of first lower plating layer 30 a located on first end surface12 e and also extends to a surface of first lower plating layer 30 a onfirst and second major surfaces 12 a and 12 b. First upper plating layer32 a may be disposed only on a surface of first lower plating layer 30 alocated on first end surface 12 e.

Second upper plating layer 32 b covers second lower plating layer 30 b.Specifically, second upper plating layer 32 b is preferably disposed ona surface of second lower plating layer 30 b located on second endsurface 12 f and also extends to a surface of second lower plating layer30 b on first and second major surfaces 12 a and 12 b. Second upperplating layer 32 b may be disposed only on a surface of second lowerplating layer 30 b located on second end surface 12 f.

In the present preferred embodiment, upper plating layer 32 has atwo-layer structure including a Ni plating layer and a Sn plating layer.The Ni plating layer covers a surface of lower plating layer 30 toprevent underlying electrode layer 26 from being eroded by solder whenmultilayer ceramic capacitor 10 is mounted on a mounting substrate. TheSn plating layer improves wettability of solder in mounting multilayerceramic capacitor 10 on the mounting substrate, and thus facilitatesmounting multilayer ceramic capacitor 10.

Upper plating layer 32 preferably has, for example, a thickness of about2 μm or more and about 11 μm or less per layer.

A dimension in length direction z of multilayer ceramic capacitor 10including multilayer body 12, first external electrode 24 a, and secondexternal electrode 24 b is indicated as a dimension L, a dimension inheight direction x of multilayer ceramic capacitor 10 includingmultilayer body 12, first external electrode 24 a, and second externalelectrode 24 b is indicated as a dimension T, and a dimension in widthdirection y of multilayer ceramic capacitor 10 including multilayer body12, first external electrode 24 a, and second external electrode 24 b isindicated as a dimension W for the sake of illustration. Multilayerceramic capacitor 10 preferably has, for example, a dimension L inlength direction z of about 0.10 mm or more and about 10.0 mm or less, adimension W in width direction y of about 0.10 mm or more and about 10.0mm or less, and a dimension T in height direction x of about 20 μm ormore and about 10.0 mm or less.

Multilayer ceramic capacitor 10 shown in FIG. 1 that includes lowerplating layer 30 that is a Cu plating layer and includes lower layerregion 40 including metal grains having a grain diameter smaller thanthat of metal grains of upper layer region 42 ensures adhesion withmultilayer body 12 by underlying electrode layer 26 defined by a thinfilm layer, and can reduce compressive stress throughout lower platinglayer 30 as lower layer region 40 includes metal grains having thesmaller grain diameter. As a result, even when thermal stress isapplied, tensile stress applied to a peripheral portion of lower platinglayer 30 can be reduced or prevented, and cracking of multilayer body 12due to the thermal stress can be reduced or prevented.

Further, multilayer ceramic capacitor 10 shown in FIG. 1 that includeslower plating layer 30 including upper layer region 42 including metalgrains having a larger grain diameter than that of metal grains of lowerlayer region 40 ensures that lower plating layer 30 is thick, and canreduce or prevent penetration of multilayer body 12 by moisture. As aresult, degradation of reliability in resistance to moisture can also beobtained.

2. Exemplary Variation of First Preferred Embodiment

Hereinafter, exemplary variations (first to third exemplary variations)of the multilayer ceramic capacitor that is the multilayer ceramicelectronic component according to the first preferred embodiment will bedescribed. For these exemplary variations, components equivalent tothose of the above preferred embodiment are denoted by the samereference characters and will not be described in details again.

(1) First Exemplary Variation

Initially, a multilayer ceramic capacitor 110 that is a multilayerceramic electronic component according to a first exemplary variation ofthe first preferred embodiment will be described. FIG. 8 is an externalperspective view of a multilayer ceramic capacitor as an example of themultilayer ceramic electronic component according to the first exemplaryvariation of the first preferred embodiment of the present invention.FIG. 9 is a front view of the multilayer ceramic capacitor as theexample of the multilayer ceramic electronic component according to thefirst exemplary variation of the first preferred embodiment of thepresent invention. FIG. 10 is a top view of the multilayer ceramiccapacitor as the example of the multilayer ceramic electronic componentaccording to the first exemplary variation of the first preferredembodiment of the present invention. FIG. 11 is a cross section takenalong a line XI-XI indicated in FIG. 1. FIG. 12 is a cross section takenalong a line XII-XII indicated in FIG. 1. FIG. 13 is a cross sectiontaken along a line XIII-XIII indicated in FIG. 1.

In multilayer ceramic capacitor 110 according to the first exemplaryvariation, as shown in FIG. 8, an external electrode 124 is disposed noton only first end surface 12 e, second end surface 12 f, first majorsurface 12 a, and second major surface 12 b, but also on first sidesurface 12 c and second side surface 12 d. Further, as shown in FIG. 13,internal electrode layer 16 includes a lead electrode portion having adifferent shape.

As shown in FIGS. 11 and 12, internal electrode layer 16 includes firstinternal electrode layer 16 a and second internal electrode layer 16 b.First internal electrode layer 16 a and second internal electrode layer16 b are alternately stacked with ceramic layer 14 interposed.

First internal electrode layer 16 a is disposed on a surface of ceramiclayer 14. First internal electrode layer 16 a includes first oppositeelectrode portion 18 a opposite to second internal electrode layer 16 b,and first lead electrode portion 20 a located on the side of one end offirst internal electrode layer 16 a and extending from first oppositeelectrode portion 18 a to first end surface 12 e of multilayer body 12.As shown in FIG. 13, first lead electrode portion 20 a includes an endportion extending to first end surface 12 e, a portion of first sidesurface 12 c, and a portion of second side surface 12 d, and thusexposed.

Second internal electrode layer 16 b is disposed on a surface of ceramiclayer 14 different from ceramic layer 14 on which first internalelectrode layer 16 a is disposed. Second internal electrode layer 16 bincludes second opposite electrode portion 18 b opposite to firstinternal electrode layer 16 a, and second lead electrode portion 20 blocated on the side of one end of second internal electrode layer 16 band extending from second opposite electrode portion 18 b to second endsurface 12 f of multilayer body 12. As shown in FIG. 13, second leadelectrode portion 20 b includes an end portion extending to second endsurface 12 f, a portion of first side surface 12 c, and a portion ofsecond side surface 12 d, and thus exposed.

External electrode 124 includes underlying electrode layer 26 andplating layer 28 covering underlying electrode layer 26.

External electrode 124 includes a first external electrode 124 a and asecond external electrode 124 b.

First external electrode 124 a is disposed on multilayer body 12 a at asurface of first end surface 12 e, a portion of first major surface 12 aand a portion of second major surface 12 b, and a portion of first sidesurface 12 c and a portion of second side surface 12 d. In this case,first external electrode 124 a is electrically connected to first leadelectrode portion 20 a of first internal electrode layer 16 a.

Second external electrode 124 b is disposed on multilayer body 12 at asurface of second end surface 12 f, a portion of first major surface 12a and a portion of second major surface 12 b, and a portion of firstside surface 12 c and a portion of second side surface 12 d. In thiscase, second external electrode 124 b is electrically connected tosecond lead electrode portion 20 b of second internal electrode layer 16b.

Further, plating layer 28 of multilayer ceramic capacitor 110 accordingto the first exemplary variation has the same or substantially the samestructure as plating layer 28 of multilayer ceramic capacitor 10.

This enables lower plating layer 30 to also be provided on first andsecond lead electrode portions 20 a and 20 b exposed at first and secondside surfaces 12 c and 12 d. As a result, external electrode 124 canalso be provided on first side surface 12 c and second side surface 12d.

Multilayer ceramic capacitor 110 of the first exemplary variation shownin FIG. 8 achieves advantageous effects that are the same as or similarto that of multilayer ceramic capacitor 10 shown in FIG. 1.

(2) Second Exemplary Variation

Subsequently, a multilayer ceramic capacitor 210 that is a multilayerceramic electronic component according to a second exemplary variationof the first preferred embodiment of the present invention will bedescribed. FIG. 14 is a central front cross section of a multilayerceramic capacitor as an example of the multilayer ceramic electroniccomponent according to the second exemplary variation of the firstpreferred embodiment of the present invention.

As shown in FIG. 14, multilayer ceramic capacitor 210 according to thesecond exemplary variation includes an external electrode 224 having anL shape in cross section. External electrode 224 includes a firstexternal electrode 224 a and a second external electrode 224 b.

In multilayer ceramic capacitor 210 that is a multilayer ceramicelectronic component according to the second exemplary variation, asshown in FIG. 14, first external electrode 224 a having an L shape incross section is disposed on a surface of first end surface 12 e, andextends from first end surface 12 e and is disposed on second majorsurface 12 b. First external electrode 224 a may include a portion thatwraps around and extends to first major surface 12 a.

Further, multilayer ceramic capacitor 210, as shown in FIG. 14, includesa second external electrode 224 b having an L shape in cross sectiondisposed on a surface of second end surface 12 f, and extending fromsecond end surface 12 f and disposed on second major surface 12 b.Second external electrode 224 b may include a portion that wraps aroundto extend to first major surface 12 a.

Therefore, in multilayer ceramic capacitor 210, on second major surface12 b, only second and fourth underlying electrode layers 26 a 2 and 26 b2 are disposed.

First external electrode 224 a may be disposed on first end surface 12 eand extend from first end surface 12 e to be disposed on first majorsurface 12 a, and second external electrode 224 b may be disposed on asurface of second end surface 12 f and extend from second end surface 12f to first major surface 12 a. First external electrode 224 a mayinclude a portion wrapped around to extend to second major surface 12 b,and second external electrode 224 b may include a portion wrapped aroundto extend to second major surface 12 b. In this case, on first majorsurface 12 a, only the first and third underlying electrode layers aredisposed.

Further, plating layer 28 of multilayer ceramic capacitor 210 accordingto the second exemplary variation has the same or substantially the samestructure as plating layer 28 of multilayer ceramic capacitor 10.

Multilayer ceramic capacitor 210 of the second exemplary variation shownin FIG. 14 achieves advantageous effects similar to those of multilayerceramic capacitor 10 shown in FIG. 1, and also has the followingadvantageous effects. That is, as external electrode 224 is not providedon a surface of first major surface 12 a, multilayer body 12 can have athickness increased by an amount corresponding to the absence of thethickness of external electrode 224, and multilayer ceramic capacitor210 can have an improved capacitance per volume. Further, in mounting,solder can be prevented from wetting an upper surface (i.e., first majorsurface 12 a) of multilayer ceramic capacitor 210, and multilayer body12 can be further increased in thickness accordingly.

(3) Third Exemplary Variation

Subsequently, a multilayer ceramic capacitor 310 that is a multilayerceramic electronic component according to a third exemplary variation ofthe first preferred embodiment of the present invention will bedescribed. FIG. 15 is a central front cross section of a multilayerceramic capacitor as an example of the multilayer ceramic electroniccomponent according to the third exemplary variation of the firstpreferred embodiment of the present invention.

As shown in FIG. 15, multilayer ceramic capacitor 310 according to thethird exemplary variation includes an external electrode 324 and a viaconnection portion 44. External electrode 324 includes a first externalelectrode 324 a and a second external electrode 324 b.

In multilayer ceramic capacitor 310 that is a multilayer ceramicelectronic component according to the third exemplary variation, asshown in FIG. 15, internal electrode layers 16 are not extending to theopposite end surfaces.

First internal electrode layer 16 a includes first opposite electrodeportion 18 a opposite to second internal electrode layer 16 b, and firstlead electrode portion 20 a located on the side of one end of firstinternal electrode layer 16 a and extending from first oppositeelectrode portion 18 a toward first end surface 12 e of multilayer body12. First lead electrode portion 20 a does not include an end thereofextending to first end surface 12 e.

Second internal electrode layer 16 b includes second opposite electrodeportion 18 b opposite to first internal electrode layer 16 a, and secondlead electrode portion 20 b located on the side of one end of secondinternal electrode layer 16 b and extending from second oppositeelectrode portion 18 b toward second end surface 12 f of multilayer body12. Second lead electrode portion 20 b does not include an end thereofextending to second end surface 12 f.

Multilayer ceramic capacitor 310 that is a multilayer ceramic electroniccomponent according to the third exemplary variation, as shown in FIG.15, includes first external electrode 324 a disposed only on secondmajor surface 12 b on the side of first end surface 12 e that definesand functions as a mounting surface. First external electrode 324 a mayinclude a portion wrapped around to extend to first end surface 12 e. Inthis case, as shown in FIG. 15, first external electrode 324 a and firstlead electrode portion 20 a of first internal electrode layer 16 a areelectrically connected by via connection portion 44.

Further, multilayer ceramic capacitor 310 that is a multilayer ceramicelectronic component according to the third exemplary variation, asshown in FIG. 15, includes second external electrode 324 b disposed onlyon second major surface 12 b on the side of second end surface 12 f thatdefines and functions as a mounting surface. Second external electrode324 b may include a portion wrapped around to extend to second endsurface 12 f. In this case, as shown in FIG. 15, second externalelectrode 324 b and second lead electrode portion 20 b of secondinternal electrode layer 16 b are electrically connected by viaconnection portion 44.

Alternatively, the mounting surface may be both first major surface 12 aand second major surface 12 b. In this case, external electrode 324 isdisposed on first major surface 12 a and second major surface 12 b onthe side of first end surface 12 e, and is disposed on first majorsurface 12 a and second major surface 12 b on the side of second endsurface 12 f. External electrode 324 may include a portion wrappedaround to extend to first end surface 12 e and second end surface 12 f.In this case as well, internal electrode layer 16 and external electrode324 are electrically connected by via connection portion 44.

As shown in FIG. 15, via connection portion 44 provides electricalconduction between internal electrode layer 16 and external electrode324. Via connection portion 44 includes a multilayer body hole 46extending through multilayer body 12 and a via connection body 48introduced in multilayer body hole 46 and connected to externalelectrode 324. First internal electrode layer 16 a includes first leadelectrode portion 20 a electrically connected to first externalelectrode 324 a by via connection body 48. Second internal electrodelayer 16 b includes second lead electrode portion 20 b electricallyconnected to second external electrode 324 b by via connection body 48.Via connection portion 44 is not limited to a circular or substantiallycircular shape in plan view, and may be a rectangular shape, a polygonalshape, an elliptical shape, or the like, for example, that can provideelectrical conduction suitably. Via connection portion 44 on the side offirst external electrode 324 a and via connection portion 44 on the sideof second external electrode 324 b may be the same or different.

Multilayer ceramic capacitor 310 of the third exemplary variation shownin FIG. 15 achieves advantageous effects similar to those of multilayerceramic capacitor 10 shown in FIG. 1, and also achieves the followingadvantageous effects. That is, as external electrode 324 is not providedon the surfaces of first major surface 12 a, and first end surface 12 eand second end surface 12 f, multilayer body 12 can have a thicknessincreased by an amount corresponding to the absence of the thickness ofexternal electrode 224, and multilayer ceramic capacitor 310 can haveimproved capacitance per volume. Further, by reducing a mounting heightand furthermore, eliminating fillet, narrowly adjacent mounting can beachieved on the mounting substrate.

While the preferred embodiment of the present invention is disclosed asdescribed above, the present invention is not limited thereto.

3. Method for Manufacturing Multilayer Ceramic Capacitor

Hereinafter, a non-limiting example of a method for manufacturing amultilayer ceramic capacitor that is an example of the multilayerceramic electronic component according to the first preferred embodimentwill be described.

Initially, a ceramic green sheet and a conductive paste for an internalelectrode are prepared. A dielectric sheet and the conductive paste forthe internal electrode layer include a binder (for example, a knownorganic binder) and a solvent (for example, a known organic binder).

Subsequently, on the ceramic green sheet, the conductive paste for theinternal electrode is printed in a predetermined pattern, for example,by screen-printing, gravure printing or the like to form an internalelectrode pattern. Specifically, a paste made of a conductive materialis applied to the ceramic green sheet in a method, such as theabove-described printing method or the like, for example, to form aconductive paste layer. The paste made of the conductive materialincludes, for example, powdery metal with an organic binder and anorganic solvent added thereto. For the ceramic green sheet, a ceramicgreen sheet provided for an outer layer and including no internalelectrode pattern printed thereon is also prepared.

A multilayer sheet is produced using such ceramic green sheets eachhaving the internal electrode pattern formed thereon. That is, apredetermined number of ceramic green sheets provided for an outer layerand including no internal electrode pattern printed thereon are stacked,a ceramic green sheet on which an internal electrode patterncorresponding to first internal electrode layer 16 a is formed and aceramic green sheet on which an internal electrode pattern correspondingto second internal electrode layer 16 b is formed are alternatelystacked thereon, and furthermore, a predetermined number of ceramicgreen sheets provided for an outer layer and including no internalelectrode pattern printed thereon are stacked thereon to prepare amultilayer sheet.

Further, the multilayer sheet is pressed in the layer stacking directionby, for example, hydrostatic pressing to prepare a multilayer block.

Subsequently, the multilayer block is cut into a predetermined size tocut out a multilayer chip. The multilayer chip may be barreled or thelike, for example to round a corner and a ridge.

Subsequently, the multilayer chip is fired to produce multilayer body12. The firing temperature is preferably about 900° C. or higher andabout 1400° C. or lower, for example, although it depends on the ceramicmaterial and the material(s) of the internal electrode.

Subsequently, underlying electrode layer 26 made of a thin film layer isformed on multilayer body 12 at a portion of first major surface 12 aand a portion of second major surface 12 b. Underlying electrode layer26 that is a thin film layer can be formed, for example, by sputteringor the like. In other words, underlying electrode layer 26 that is athin film layer is configured as a sputtered electrode. The sputteredelectrode can be formed of a metal including at least one selected fromNi, Cr, Cu, Ti, and the like, for example.

Thereafter, a Cu plating layer as lower plating layer 30 is formed so asto directly cover underlying electrode layer 26 made of a thin filmlayer, and multilayer body 12 on first and second end surfaces 12 e and12 f on which underlying electrode layer 26 is not disposed. To formlower plating layer 30, for example, electroplating using anelectroplating bath with an additive added thereto or electrolessplating by substitution reaction is performed. By changing a platingcondition, lower layer region 40 located on the side of multilayer body12 and upper layer region 42 located on a surface of lower layer region40 are formed in lower plating layer 30. The plating condition includes,for example, bath temperature, bath ion concentration, and currentdensity for electrolytic plating. Thus, lower layer region 40 can beformed of metal grains having a grain diameter smaller than that ofmetal grains configuring upper layer region 42.

Subsequently, upper plating layer 32 is formed on a surface of lowerplating layer 30. Upper plating layer 32 includes, for example, at leastone selected from Cu, Ni, Sn, Ag, Pd, Ag—Pd alloy, Au, and the like, andis formed of a single layer or a plurality of layers. Preferably, upperplating layer 32 includes a Ni plating layer and a Sn plating layerformed on the Ni plating layer, and is thus including two layers.

Multilayer ceramic capacitor 10 shown in FIG. 1 can thus bemanufactured.

The method for manufacturing a multilayer ceramic capacitor according tothe present preferred embodiment as described above enables a multilayerceramic capacitor according to the present preferred embodiment whichprovides high performance to be manufactured with high quality.

B. Second Preferred Embodiment 1. Multilayer Ceramic Capacitor

Hereinafter, a multilayer ceramic capacitor according to a secondpreferred embodiment of the present invention will be described. FIG. 16is an external perspective view of a multilayer ceramic capacitor as anexample of the multilayer ceramic electronic component according to thesecond preferred embodiment of the present invention. FIG. 17 is a crosssection taken along a line XVII-XVII indicated in FIG. 16. FIG. 18 is across section taken along a line XVIII-XVIII indicated in FIG. 16. FIG.19 is a cross section taken along a line XIX-XIX indicated in FIG. 16.FIG. 20 is an exploded perspective view of a multilayer body shown inFIG. 16. FIG. 21A shows a first internal electrode pattern of themultilayer ceramic capacitor shown in FIG. 16. FIG. 21B shows a secondinternal electrode pattern of the multilayer ceramic capacitor shown inFIG. 16. FIG. 22 is a schematic cross section for illustrating astructure of an external electrode according to the present invention.FIG. 23 is a schematic cross section for illustrating a structure of anexternal electrode according to the present invention.

A multilayer ceramic capacitor 510 includes a multilayer body 512 andexternal electrodes 524 and 525.

Multilayer body 512 includes a plurality of ceramic layers 514 and aplurality of internal electrode layers 516. Multilayer body 512 includesa first major surface 512 a and a second major surface 512 b opposite toeach other in height direction x, a first side surface 512 c and asecond side surface 512 d opposite to each other in width direction yorthogonal or substantially orthogonal to height direction x, and athird end surface 512 e and a fourth end surface 512 f opposite to eachother in length direction z orthogonal or substantially orthogonal toheight direction x and width direction y. First major surface 512 a andsecond major surface 512 b each extend in width direction y and lengthdirection z. First side surface 512 c and second side surface 512 d eachextend in height direction x and width direction z. Third side surface512 e and fourth side surface 512 f each extend in height direction xand length direction y. Accordingly, height direction x is a directionconnecting first major surface 512 a and second major surface 512 b,width direction y is a direction connecting first side surface 512 c andsecond side surface 512 d, and length direction z is a directionconnecting third side surface 512 e and fourth side surface 512 f.

Multilayer body 512 preferably includes a corner and a ridge that arerounded. A corner is a portion where three surfaces of multilayer body512 meet one another, and a ridge is a portion where two surfaces ofmultilayer body 512 meet each other.

As shown in FIGS. 17 and 18, in height direction x connecting firstmajor surface 512 a and second major surface 512 b, multilayer body 512includes an effective layer portion 515 a in which the plurality ofinternal electrode layers 516 are opposite to one other, a first outerlayer portion 515 b 1 including a plurality of ceramic layers 514located between an internal electrode layer 516 located closest to firstmajor surface 512 a and first major surface 512 a, and a second outerlayer portion 515 b 2 including a plurality of ceramic layers 514located between an internal electrode layer 516 located closest tosecond major surface 512 b and second major surface 512 b.

First outer layer portion 515 b 1 includes a plurality of ceramic layers514 located on a side of multilayer body 512 closer to first majorsurface 512 a between first major surface 512 a and internal electrodelayer 516 closest to first major surface 512 a.

Second outer layer portion 515 b 2 includes a plurality of ceramiclayers 514 located on a side of multilayer body 512 closer to secondmajor surface 512 b between second major surface 512 b and internalelectrode layer 516 closest to second major surface 512 b.

A region sandwiched between first outer layer portion 515 b 1 and secondouter layer portion 515 b 2 is effective layer portion 515 a. While thenumber of ceramic layers 514 that are stacked is not particularlylimited, preferably, for example, 15 or more and 70 or less ceramiclayers 514 are stacked including first outer layer portion 515 b 1 andsecond outer layer portion 515 b 2. Ceramic layer 514 preferably has athickness of, for example, about 0.4 μm or more and about 10 μm or less.First outer layer portion 515 a and second outer layer portion 515 b 2preferably have a thickness of, for example, about 3 μm or more andabout 15 μm or less. A region sandwiched between both outer layerportions 515 b 1 and 515 b 2 is effective layer portion 515 b. That is,effective layer portion 515 a is a region in which internal electrodelayers 416 are stacked.

Ceramic layer 514 can be made of, for example, a dielectric material.The dielectric material can, for example, be a dielectric ceramicmaterial including BaTiO₃, CaTiO₃, SrTiO₃, CaZnO₃ or the like as a maincomponent. Further, the material may include these as a main componentand an Mn compound, an Fe compound, a Cr compound, a Co compound, a Nicompound or the like added thereto as a subcomponent.

While multilayer body 512 is not particularly limited in dimension, forexample, it preferably has a dimension L of about 0.43 mm or more andabout 0.73 mm or less, about 0.85≤W/L≤about 1.0, and a dimension T ofabout 50 μm or more and about 5 90 μm or less.

As shown in FIGS. 17 to 20, internal electrode layer 516 includes aplurality of first internal electrode layers 516 a and a plurality ofsecond internal electrode layers 516 b. First internal electrode layer516 a and second internal electrode layer 516 b are alternately stackedwith ceramic layer 514 interposed therebetween.

First internal electrode layer 516 a is disposed on a surface of ceramiclayer 514. First internal electrode layer 516 a includes a firstopposite electrode portion 518 a opposite to first major surface 512 aand second major surface 512 b and opposite to second internal electrodelayer 516 b, and is stacked in a direction connecting first majorsurface 512 a and second major surface 512 b.

Second internal electrode layer 516 b is disposed on a surface of aceramic layer 514 different from ceramic layer 514 on which firstinternal electrode layer 516 a is disposed. Second internal electrodelayer 516 b includes a second opposite electrode portion 518 b oppositeto first major surface 512 a and second major surface 512 b, and isstacked in a direction connecting first major surface 512 a and secondmajor surface 512 b.

As shown in FIGS. 19 to 21B, first internal electrode layer 516 a isextending to first and third side surfaces 512 c and 512 e of multilayerbody 512 by a first lead electrode portion 520 a, and is extending tosecond and fourth side surfaces 512 d and 512 f of multilayer body 512by a second lead electrode portion 520 b. A width of first leadelectrode portion 520 a extending to first side surface 512 c may beequal or substantially equal to that of first lead electrode portion 520a extending to third side surface 512 e, and a width of second leadelectrode portion 520 b extending to second side surface 512 d may beequal or substantially equal to that of second lead electrode portion520 b extending to fourth side surface 512 f. That is, first leadelectrode portion 520 a is extending to the side of third side surface512 e of multilayer body 512, and second lead electrode portion 520 b isextending to the side of fourth side surface 512 f of multilayer body512.

Second internal electrode layer 516 b is extending to first and fourthside surfaces 512 c and 512 f of multilayer body 512 by a third leadelectrode portion 521 a, and is extending to second and third sidesurfaces 512 d and 512 e of multilayer body 512 by a fourth leadelectrode portion 521 b. A width of third lead electrode portion 521 aextending to first side surface 512 c may be equal or substantiallyequal to that of third lead electrode portion 521 a extending to fourthside surface 512 f, and a width of fourth lead electrode portion 521 bextending to second side surface 512 d may be equal or substantiallyequal to that of fourth lead electrode portion 521 b extending to thirdside surface 512 e. That is, third lead electrode portion 521 a isextending to the side of fourth side surface 512 f of multilayer body512, and fourth lead electrode portion 521 b is extending to the side ofthird side surface 512 c of multilayer body 512.

When multilayer ceramic capacitor 510 is seen in the layer stackingdirection, it is preferable that a straight line connecting first andsecond lead electrode portions 520 a and 520 b of first internalelectrode layer 516 a and a straight line connecting third and fourthlead electrode portions 521 a and 521 b of second internal electrodelayer 516 b intersect with each other.

Further, it is preferable that, at side surfaces 512 c, 512 d, 512 e and512 f of multilayer body 512, first lead electrode portion 520 a offirst internal electrode layer 516 a and fourth lead electrode portion521 b of second internal electrode layer 516 b extend to locationsopposite to each other, and second lead electrode portion 520 b of firstinternal electrode layer 516 a and third lead electrode portion 521 a ofsecond internal electrode layer 516 b extend to locations opposite toeach other.

As shown in FIG. 19, multilayer body 512 includes a side portion (an Lgap) 522 b of multilayer body 512 between one end in length direction zof first opposite electrode portion 518 a and third side surface 512 eand between the other end in length direction z of second oppositeelectrode portion 518 a and fourth side surface 512 f. Multilayer body512 preferably includes side portion (or L gap) 522 b with an averagelength in width direction z of, for example, about 10 μm or more andabout 60 μm or less, more preferably about 10 μm or more and about 30 μmor less, and still more preferably about 10 μm or more and about 20 μmor less.

Further, as shown in FIG. 19, multilayer body 512 includes a sideportion (a W gap) 522 a of multilayer body 512 between one end in widthdirection y of first opposite electrode portion 518 a and first sidesurface 512 c, and between the other end in width direction y of secondopposite electrode portion 518 a and second side surface 512 d.Multilayer body 512 preferably has side portion (or W gap) 522 a with anaverage length in length direction y of, for example, about 10 μm ormore and about 60 μm or less, more preferably about 10 μm or more andabout 30 μm or less, and still more preferably about 10 μm or more andabout 20 μm or less.

Internal electrode layer 516 can be made of material including, forexample, metal such as Ni, Cu, Ag, Pd, Au or the like, or an alloyincluding one of these metals, such as an Ag—Pd alloy. Internalelectrode layer 516 may further include dielectric grains having thesame or substantially the same composition as a ceramic materialincluded in ceramic layer 514. Preferably, for example, 20 or more and80 or less internal electrode layers 516 are stacked. Internal electrodelayers 516 preferably have an average thickness of, for example, about0.2 μm or more and about 2.0 μm or less.

As shown in FIGS. 16 to 19, external electrodes 524 and 525 are disposedon multilayer body 512.

External electrode 524 includes an underlying electrode layer 526 and aplating layer 528 covering underlying electrode layer 526. Externalelectrode 525 includes an underlying electrode layer 527 and a platinglayer 529 covering underlying electrode layer 527.

External electrode 524 includes a first external electrode 524 a and asecond external electrode 524 b.

First external electrode 524 a covers first lead electrode portion 520 aon first side surface 512 c and third side surface 512 e, and covers aportion of first and second major surfaces 512 a and 512 b. Firstexternal electrode 524 a is electrically connected to first leadelectrode portion 520 a of first internal electrode layer 516 a.

Second external electrode 524 b covers second lead electrode portion 520b on second side surface 512 d and fourth side surface 512 f, and coversa portion of first and second major surfaces 512 a and 512 b. Secondexternal electrode 524 b is electrically connected to second leadelectrode portion 520 b of first internal electrode layer 516 a.

External electrode 525 includes a third external electrode 525 a and afourth external electrode 525 b.

Third external electrode 525 a covers third lead electrode portion 521 aon first side surface 512 c and fourth side surface 512 f, and covers aportion of first and second major surfaces 512 a and 512 b. Thirdexternal electrode 525 a is electrically connected to third leadelectrode portion 521 a of second internal electrode layer 516 b.

Fourth external electrode 525 b covers fourth lead electrode portion 521b on second side surface 512 d and third side surface 512 e, and coversa portion of first and second major surfaces 512 a and 512 b. Fourthexternal electrode 525 b is electrically connected to fourth leadelectrode portion 521 b of second internal electrode layer 516 b.

In multilayer body 512, first opposite electrode portion 518 a of firstinternal electrode layer 516 a and second opposite electrode portion 518b of second internal electrode layer 516 b are opposite to each otherwith ceramic layer 514 interposed therebetween to generate capacitance.Therefore, capacitance can be obtained between first and second externalelectrodes 524 a and 524 b to which first internal electrode layer 516 ais connected and third and fourth external electrodes 525 a and 525 b towhich second internal electrode layer 516 b is connected, and capacitorcharacteristics are produced.

Underlying electrode layer 526 includes a first underlying electrodelayer 526 a 1, a second underlying electrode layer 526 a 2, a thirdunderlying electrode layer 526 b 1, and a fourth underlying electrodelayer 526 b 2. First underlying electrode layer 526 a 1, secondunderlying electrode layer 526 a 2, third underlying electrode layer 526b 1, and fourth underlying electrode layer 526 b 2 are defined by a thinfilm layer including a plurality of thin film electrodes to furtherimprove performance.

First underlying electrode layer 526 a 1 covers a portion of first majorsurface 512 a at a corner where first major surface 512 a, first sidesurface 512 c, and third side surface 512 e meet one another. Secondunderlying electrode layer 526 a 2 covers a portion of second majorsurface 512 b at a corner where second major surface 512 b, first sidesurface 512 c, and third side surface 512 e meet one another. Thirdunderlying electrode layer 526 b 1 covers a portion of first majorsurface 512 a at a corner where first major surface 512 a, second sidesurface 512 b, and fourth side surface 512 d meet one another. Fourthunderlying electrode layer 526 b 2 covers a portion of second majorsurface 512 b at a corner where second major surface 512 b, second sidesurface 512 b, and fourth side surface 512 d meet one another.

Underlying electrode layer 527 includes a fifth underlying electrodelayer 527 a 1, a sixth underlying electrode layer 527 a 2, a seventhunderlying electrode layer 527 b 1, and an eighth underlying electrodelayer 527 b 2. Fifth underlying electrode layer 527 a 1, sixthunderlying electrode layer 527 a 2, seventh underlying electrode layer527 b 1, and eighth underlying electrode layer 527 b 2 are each definedby a thin film layer including a plurality of thin film electrodes forfurther enhanced performance.

Fifth underlying electrode layer 527 a 1 covers a portion of first majorsurface 512 a at a corner where first major surface 512 a, first sidesurface 512 c, and fourth side surface 512 d meet one another. Sixthunderlying electrode layer 527 a 2 covers a portion of second majorsurface 512 b at a corner where second major surface 512 b, first sidesurface 512 c, and fourth side surface 512 d meet one another. Seventhunderlying electrode layer 527 b 1 covers a portion of first majorsurface 512 a at a corner where first major surface 512 a, second sidesurface 512 b, and third side surface 512 e meet one another. Eighthunderlying electrode layer 527 b 2 covers a portion of second majorsurface 512 b at a corner where second major surface 512 b, second sidesurface 512 b, and third side surface 512 e meet one another.

Underlying electrode layers 526, 527 defined by the thin film layer ispreferably formed in a thin film formation method such as sputtering orvapor deposition, for example. In particular, underlying electrode layer526, 527 defined by the thin film layer is preferably a sputteredelectrode formed by sputtering. Hereinafter, an electrode formed bysputtering will be described.

When a sputtered electrode defines and functions as underlying electrodelayer 526, 527, it is preferable to form the sputtered electrodedirectly on multilayer body 512 at a portion of first major surface 512a and a portion of second major surface 512 b.

Underlying electrode layer 526, 527 that is the sputtered electrodepreferably includes, for example, at least one selected from Ni, Cr, Cu,Ti, and the like.

The sputtered electrode in height direction x connecting first majorsurface 512 a and second major surface 512 b preferably has a thicknessof, for example, about 50 nm or more and about 400 nm or less, and morepreferably about 50 nm or more and about 130 nm or less.

Plating layer 528 includes a first plating layer 528 a and a secondplating layer 528 b. First plating layer 528 a covers first underlyingelectrode layer 526 a 1 and second underlying electrode layer 526 a 2.Second plating layer 528 b covers third underlying electrode layer 526 b1 and fourth underlying electrode layer 527 b 2.

Plating layer 529 includes a third plating layer 529 a and a fourthplating layer 529 b. Third plating layer 529 a covers fifth underlyingelectrode layer 527 a 1 and sixth underlying electrode layer 527 a 2.Fourth plating layer 529 b covers seventh underlying electrode layer 527b 1 and eighth underlying electrode layer 528 b 2.

Plating layer 528 and plating layer 529 may each include a plurality oflayers. Preferably, plating layer 528 includes a lower plating layer 530covering underlying electrode layer 526 and an upper plating layer 532covering lower plating layer 530. Similarly, plating layer 529 includesa lower plating layer 531 covering underlying electrode layer 527 and anupper plating layer 533 covering lower plating layer 531. Of platinglayer 528, upper plating layer 532 preferably includes, for example, atleast one selected from Ni, Sn, Cu, Ag, Pd, Ag—Pd alloy, Au, and thelike. Similarly, of plating layer 529, upper plating layer 533preferably includes, for example, at least one selected from Ni, Sn, Cu,Ag, Pd, Ag—Pd alloy, Au, and the like.

Lower plating layer 530 includes a first lower plating layer 530 a and asecond lower plating layer 530 b.

First lower plating layer 530 a is disposed on multilayer body 512 atfirst and third side surfaces 512 c and 512 e free of the underlyingelectrode layer, and further covers first underlying electrode layer 526a 1 disposed on first major surface 512 a and second underlyingelectrode layer 526 a 2 disposed on second major surface 512 b.

Second lower plating layer 530 b is disposed on multilayer body 512 atsecond and fourth side surfaces 512 b and 512 f free of the underlyingelectrode layer, and further covers third underlying electrode layer 526b 1 disposed on first major surface 512 a and fourth underlyingelectrode layer 526 b 2 disposed on second major surface 512 b.

Lower plating layer 531 includes a third lower plating layer 531 a and afourth lower plating layer 531 b.

Third lower plating layer 531 a is disposed on multilayer body 512 atfirst and fourth side surfaces 512 c and 512 f free of the underlyingelectrode layer, and further covers fifth underlying electrode layer 527a 1 disposed on first major surface 512 a and sixth underlying electrodelayer 527 a 2 disposed on second major surface 512 b.

Fourth lower plating layer 531 b is disposed on multilayer body 512 atsecond and third side surfaces 512 b and 512 e free of the underlyingelectrode layer, and further covers seventh underlying electrode layer527 b 1 disposed on first major surface 512 a and eighth underlyingelectrode layer 527 b 2 disposed on second major surface 512 b.

This enables a second plating layer (i.e., upper plating layers 532,533) to have a uniform or substantially uniform thickness and can, thus,effectively reduce or prevent variation in thickness of the secondplating layer (i.e., upper plating layers 532, 533) et. seq.

In the present preferred embodiment, lower plating layers 530, 531preferably includes Cu, for example. Accordingly, lower plating layers530 and 531 are defined by Cu plating layers. Lower plating layers 530,531 are defined by Cu plating layers and cover a surface of underlyingelectrode layer 526 and that of underlying electrode layer 527 toeffectively reduce or prevent penetration by a plating solution.

Further, as shown in FIG. 22, lower plating layer 530 includes a lowerlayer region 540 located on the side of multilayer body 512 and an upperlayer region 542 located between lower layer region 540 and upperplating layer 532. Further, metal grains of a Cu plating layer locatedin lower layer region 540 have a smaller grain diameter than that ofmetal grains of a Cu plating layer located in upper layer region 542.

Further, as shown in FIG. 23, lower plating layer 531 includes a lowerlayer region 541 located on the side of multilayer body 512 and an upperlayer region 543 located between lower layer region 541 and upperplating layer 533. Further, metal grains of a Cu plating layer locatedin lower layer region 541 have a smaller grain diameter than that ofmetal grains of a Cu plating layer located in upper layer region 543.

Note that a grain diameter of metal grains of a Cu plating layer means amaximum grain diameter of the Cu plating layer in the direction of thethickness thereof.

Lower plating layer 530 including lower layer region 540 with grainshaving a smaller grain diameter than that of metal grains of a Cuplating layer located in upper layer region 542 can have a reducedcompressive stress. Further, lower plating layer 531 including lowerlayer region 541 with grains having a smaller grain diameter than thatof metal grains of a Cu plating layer located in upper layer region 543can have a reduced compressive stress. As a result, even when thermalstress is applied, tensile stress applied to a peripheral portion oflower plating layers 530, 531 can be reduced or prevented, and crackingof multilayer body 512 due to the thermal stress can be reduced orprevented. Further, lower plating layer 530 including upper layer region542 with metal grains having a larger grain diameter than that of metalgrains of lower layer region 540 and lower plating layer 531 includingupper layer region 543 with metal grains having a larger grain diameterthan that of metal grains configuring lower layer region 540 are ensuredto be thick and can reduce or prevent penetration of multilayer body 512by moisture. As a result, satisfactorily reliable resistance to moisturecan be maintained while stress caused by application of thermal stressis reduced. Note that while in lower plating layer 530, upper layerregion 542 includes metal grains having a large grain diameter, and inlower plating layer 531, upper layer region 543 includes metal grainshaving a large grain diameter, and accordingly, tensile stress due tothermal stress may be generated, lower layer regions 540 and 541 thatinclude metal grains having a small diameter define and function as abarrier layer, and can reduce or prevent cracking attributed to stresscaused in upper layer regions 542 and 543.

Lower layer region 540 of lower plating layer 530 preferably has asmaller thickness than upper layer region 542 of lower plating layer530. Further, lower layer region 541 of lower plating layer 531preferably has a smaller thickness than upper layer region 543 of lowerplating layer 531. This can reduce compressive stress caused in lowerplating layers 530 and 531 by application of thermal cycle with respectto multilayer body 512, and effectively reduce or prevent cracking ofmultilayer body 512 due to the compressive stress.

Lower layer region 540 of lower plating layer 530 and lower layer region541 of lower plating layer 531 preferably have a thickness of, forexample, about 0.2 μm or more and about 1.0 μm or less. When lower layerregion 540 of lower plating layer 530 and lower layer region 541 oflower plating layer 531 have a thickness smaller than about 0.2 μm,lower layer regions 540 and 541 defined by Cu plating will be formeddiscontinuously, and for example, multilayer ceramic capacitor 510 maynot be reliably moisture-resistant. In contrast, when lower layer region540 of lower plating layer 530 and lower layer region 541 of lowerplating layer 531 have a thickness larger than about 1.0 μm, theexternal electrode may include an end portion unsatisfactorily formed asplating is grown.

Upper layer region 542 of lower plating layer 530 and upper layer region543 of lower plating layer 531 preferably have a thickness of, forexample, about 4.0 μm or more and about 8.0 μm or less. When upper layerregion 542 of lower plating layer 530 and upper layer region 543 oflower plating layer 531 have a thickness smaller than about 4.0 μm,upper layer regions 542 and 543 defined by Cu plating will be formeddiscontinuously, and for example, multilayer ceramic capacitor 510 maynot be reliably moisture-resistant. In contrast, when upper layer region542 of lower plating layer 530 and upper layer region 543 of lowerplating layer 531 have a thickness larger than about 8.0 μm, theelemental body has a thickness reduced by the amount of the thickness ofthe plating, and capacitance, strength and the like may not be obtainedas desired.

Lower layer region 540 of lower plating layer 530 preferably includesmetal grains having a grain diameter of, for example, about 0.20 μm orless, and upper layer region 542 of lower plating layer 530 preferablyincludes metal grains having a grain diameter of, for example, about0.50 μm or more. Lower layer region 541 of lower plating layer 531preferably includes metal grains having a grain diameter of, forexample, about 0.20 μm or less, and upper layer region 543 of lowerplating layer 531 preferably includes metal grains having a graindiameter of, for example, about 0.50 μm or more. Thus, a stressrelaxation effect of lower layer regions 540 and 541 of lower platinglayers 530 and 531 can reduce compressive stress caused by applicationof thermal stress with respect to multilayer body 512, and effectivelyreduce or prevent cracking of multilayer body 12 due to the compressivestress. Further, by the metal grains of upper layer regions 542, 543 oflower plating layers 530, 531, an advantageous effect is obtained toreduce or prevent unsatisfactory formation of an end portion of theexternal electrode due to growth of plating. This is because ensuringthat lower layer region 540 of lower plating layer 530 and lower layerregion 541 of lower plating layer 531 are continuous requires providinga sufficient thickness, and in forming a prescribed thickness, using abath allowing metal grains to be formed with a small grain diameterfacilitates growth of plating. When lower layer region 540 of lowerplating layer 530 and lower layer region 541 of lower plating layer 531include metal grains having a grain diameter larger than about 0.20 μm,compressive stress by application of thermal stress with respect tomultilayer body 512 increases, and cracking of multilayer body 512 dueto this compression stress may occur. In contrast, when upper layerregion 542 of lower plating layer 530 and upper layer region 543 oflower plating layer 531 include metal grains having a grain diametersmaller than about 0.5 μm, upper layer regions 542, 543 of lower platinglayers 530, 531 will be discontinuous, and, for example, multilayerceramic capacitor 510 may not be reliably moisture-resistant.

Upper plating layer 532 includes a first upper plating layer 532 a and asecond upper plating layer 532 b.

First upper plating layer 532 a covers first lower plating layer 530 a.Specifically, first upper plating layer 532 a is preferably disposed ona surface of first lower plating layer 530 a located on first and thirdside surfaces 512 c and 512 e and also extends to first and second majorsurfaces 512 a and 512 b on a surface of first lower plating layer 530a.

Second upper plating layer 532 b covers second lower plating layer 530b. Specifically, second upper plating layer 532 b is preferably disposedon a surface of second lower plating layer 530 b located on second andfourth side surfaces 512 b and 512 f and also extends to first andsecond major surfaces 512 a and 512 b on a surface of second lowerplating layer 530 b.

Upper plating layer 533 includes a third upper plating layer 533 a and afourth upper plating layer 533 b.

First upper plating layer 533 a covers first lower plating layer 531 a.Specifically, first upper plating layer 533 a is preferably disposed ona surface of first lower plating layer 531 a located on first and fourthside surfaces 512 c and 512 f and also extends to first and second majorsurfaces 512 a and 512 b on a surface of first lower plating layer 531a.

Second upper plating layer 533 b covers second lower plating layer 531b. Specifically, second upper plating layer 533 b is preferably disposedon a surface of second lower plating layer 531 b located on second andthird side surfaces 512 b and 512 e and also extends to first and secondmajor surfaces 512 a and 512 b on a surface of second lower platinglayer 531 b.

In the present preferred embodiment, upper plating layers 532, 533 havea two-layer structure including a Ni plating layer followed by a Snplating layer, for example. The Ni plating layer can cover a surface oflower plating layer 30 to prevent underlying electrode layers 526, 527from being eroded by solder when multilayer ceramic capacitor 510 ismounted on a mounting substrate. The Sn plating layer can be provided toimprove wettability of solder in mounting multilayer ceramic capacitor510 on the mounting substrate, and thus facilitate mounting multilayerceramic capacitor 510.

Upper plating layers 532, 533 are preferably, for example, about 2 μm ormore and about 11 μm or less in thickness per layer.

A dimension in length direction z of multilayer ceramic capacitor 510including multilayer body 512 and external electrodes 524 and 525 isindicated as a dimension L, a dimension in height direction x ofmultilayer ceramic capacitor 510 including multilayer body 512 andexternal electrodes 524 and 525 is indicated as a dimension T, and adimension in width direction y of multilayer ceramic capacitor 510including multilayer body 512 and electrodes 524 and 525 is indicated asa dimension W for the sake of illustration. Multilayer ceramic capacitor510 preferably, for example, has a dimension L in length direction z ofabout 0.45 mm or more and about 0.75 mm or less, a dimension T in heightdirection x of about 70 μm or more and about 110.0 mm or less, and adimension W in width direction y to satisfy about 0.85 W/L about 1.0.

Multilayer ceramic capacitor 510 shown in FIG. 16 achieves advantageouseffects similar to those of multilayer ceramic capacitor 10 describedabove.

2. Exemplary Variation of Second Preferred

Subsequently, a multilayer ceramic capacitor according to an exemplaryvariation of the second preferred embodiment of the present inventionwill be described. FIG. 24A is an external perspective view of amultilayer ceramic capacitor as an example of a multilayer ceramicelectronic component according to an exemplary variation of the secondpreferred embodiment of the present invention. FIG. 24B is a bottom viewof the multilayer ceramic capacitor as the example of the multilayerceramic electronic component according to the exemplary variation of thesecond preferred embodiment of the present invention. Any component ofmultilayer ceramic capacitor 510′ shown in FIGS. 24A and 24B that isidentical to that of multilayer ceramic capacitor 510 shown in FIGS. 16to 23 is identically denoted will not be described repeatedly.

Multilayer ceramic capacitor 510′ includes a rectangular orsubstantially rectangular parallelepiped multilayer body 512 andexternal electrodes 524′ and 525′.

External electrode 524′ includes a first external electrode 524 a′electrically connected to first lead electrode portion 518 a of firstinternal electrode layer 516 a, and a second external electrode 524 b′electrically connected to second lead electrode portion 520 b.

First external electrode 524 a′ covers first lead electrode portion 520a on first side surface 512 c and third side surface 512 e, and covers aportion of second major surface 512 b. Second external electrode 524 b′covers second lead electrode portion 520 b on second side surface 512 dand fourth side surface 512 f, and covers a portion of second majorsurface 512 b.

External electrode 525′ includes a third external electrode 525 a′electrically connected to third lead electrode portion 521 a of secondinternal electrode layer 516 b, and a fourth external electrode 525 b′electrically connected to fourth lead electrode portion 521 b.

Third external electrode 525 a′ covers third lead electrode portion 521a on first side surface 512 c and fourth side surface 512 f, and coversa portion of second major surface 512 b. Fourth external electrode 525b′ covers fourth lead electrode portion 521 b on second side surface 512d and third side surface 512 e, and covers a portion of second majorsurface 512 b.

External electrodes 524′ and 525′ preferably include an underlyingelectrode layer and a plating layer in this order from the side ofmultilayer body 512.

Further, plating layers 530 and 531 of multilayer ceramic capacitor 510′according to the present exemplary variation has the same orsubstantially the same structure as plating layers 530 and 531 ofmultilayer ceramic capacitor 510.

Multilayer ceramic capacitor 510′ shown in FIGS. 24A and 24B achievesadvantageous effects similar to that of multilayer ceramic capacitor 510described above, and also achieves the following advantageous effects.That is, as external electrodes 524′ and 525′ are not provided on asurface of second major surface 12 b, multilayer body 512 can have athickness increased by an amount corresponding to the absence of thethickness of the external electrodes, and multilayer ceramic capacitor510′ can have improved strength, and capacitance per volume. Further, inmounting, solder can be prevented from wetting an upper surface (i.e.,second major surface 512 b) of multilayer ceramic capacitor 510′, andmultilayer body 512 can further be increased in thickness accordingly.

3. Method for Manufacturing Multilayer Ceramic Capacitor

Hereinafter, a non-limiting example of a method for manufacturingmultilayer ceramic capacitors 510 and 510′ will be described.

Initially, a ceramic green sheet and a conductive paste for an internalelectrode are prepared. The ceramic green sheet and the conductive pastefor the internal electrode layer include a binder (for example, a knownorganic binder) and a solvent (for example, an organic solvent).

Subsequently, on the ceramic green sheet, the conductive paste for theinternal electrode is printed in a predetermined pattern, for example,by screen-printing, gravure printing or the like to form an internalelectrode pattern such as shown in FIGS. 21A and 21B. Specifically, apaste made of a conductive material is applied to the ceramic greensheet in a method such as the above-described printing method or thelike, for example, to form a conductive paste layer. The paste made ofthe conductive material includes, for example, powdery metal with anorganic binder and an organic solvent added thereto. For the ceramicgreen sheet, a ceramic green sheet provided for an outer layer andincluding no internal electrode pattern printed thereon is alsoprepared.

A multilayer sheet is produced using such ceramic green sheets eachincluding the internal electrode pattern formed thereon. That is, apredetermined number of ceramic green sheets provided for an outer layerand including no internal electrode pattern printed thereon are stacked,a ceramic green sheet on which an internal electrode patterncorresponding to first internal electrode layer 516 a is formed and aceramic green sheet on which an internal electrode pattern correspondingto second internal electrode layer 516 b is formed are alternatelystacked thereon, and furthermore, a predetermined number of ceramicgreen sheets including no internal electrode pattern printed thereon arestacked thereon to prepare a multilayer sheet.

Subsequently, the multilayer body sheet is pressed in the layer stackingdirection by, for example, hydrostatic pressing to prepare a multilayerbody block.

Further, the multilayer sheet is pressed in the layer stacking directionby, for example, hydrostatic pressing to prepare a multilayer block.

Subsequently, the multilayer block is cut into a predetermined size toproduce a multilayer chip. The multilayer chip may be barreled or thelike, for example, to round a corner and a ridge.

Subsequently, the multilayer chip is fired to produce multilayer body512 such as shown in FIG. 25. The firing temperature is preferably about900° C. or higher and about 1300° C. or lower, for example, although itdepends on the ceramic material and the material(s) of the internalelectrode.

As shown in FIG. 25, first lead electrode portion 520 a of firstinternal electrode layer 516 a is exposed from first and third sidesurfaces 512 c and 512 e of multilayer body 512, and third leadelectrode portion 521 a of second internal electrode layer 516 b isexposed from first and fourth side surfaces 512 c and 512 f ofmultilayer body 512. Further, second lead electrode portion 520 b offirst internal electrode layer 516 a is exposed from second and fourthside surfaces 512 d and 512 f of multilayer body 512, and fourth leadelectrode portion 521 b of second internal electrode layer 516 b isexposed from second and third side surfaces 512 d and 512 e ofmultilayer body 512.

Subsequently, as shown in FIG. 26, underlying electrode layers 526 and527 each defined by a thin film electrode layer are formed on multilayerbody 512 at a portion of first major surface 512 a and a portion ofsecond major surface 512 b. Underlying electrode layers 526 and 527 thatare a thin film layer can be formed, for example, by sputtering or thelike. In other words, an underlying electrode layer that is a thin filmlayer is defined by a sputtered electrode. The sputtered electrode canbe formed of a metal including at least one selected from Ni, Cr, Cu,Ti, and the like, for example.

When external electrodes 524′ and 525′ are formed such that no externalelectrode is disposed on first major surface 512 a, as in multilayerceramic capacitor 510′, underlying electrode layers 526 and 527 are notformed on first major surface 512 a.

Subsequently, a Cu plating layer defining and functioning as first lowerplating layer 530 a is formed to be disposed on multilayer body 512 atfirst and third side surfaces 512 c and 512 e free of the underlyingelectrode layer, and furthermore, cover first underlying electrode layer526 a 1 disposed on first major surface 512 a and second underlyingelectrode layer 526 a 2 disposed on second major surface 512 b, and a Cuplating layer defining and functioning as second lower plating layer 530b is formed to be disposed on multilayer body 512 at second and fourthside surfaces 512 b and 512 f free of the underlying electrode layer,and furthermore, cover third underlying electrode layer 526 b 1 disposedon first major surface 512 a and fourth underlying electrode layer 526 b2 disposed on second major surface 512 b. Further, a Cu plating layerdefining and functioning as third lower plating layer 531 a is formed tobe disposed on multilayer body 512 at first and fourth side surfaces 512c and 512 f free of the underlying electrode layer, and furthermore,cover fifth underlying electrode layer 527 a 1 disposed on first majorsurface 512 a and sixth underlying electrode layer 527 a 2 disposed onsecond major surface 512 b, and a Cu plating layer defining andfunctioning as fourth lower plating layer 531 b is formed to be disposedon multilayer body 512 at second and third side surfaces 512 b and 512 efree of the underlying electrode layer, and furthermore, cover seventhunderlying electrode layer 527 b 1 disposed on first major surface 512 aand eighth underlying electrode layer 527 b 2 disposed on second majorsurface 512 b. In forming lower plating layers 530 a, 530 b, 531 a and531 b, electroplating using an electroplating bath with an additiveadded thereto or electroless plating by substitution reaction isperformed. By changing a plating condition, lower layer regions 540 and541 located on the side of multilayer body 512 and upper layer regions542 and 543 located on the surfaces of lower layer regions 540 and 541are formed in lower plating layers 530 a, 530 b, 531 a and 531 b. Theplating condition includes, for example, bath temperature, bath ionconcentration, and current density for electrolytic plating. Thus, lowerlayer regions 540, 541 can be formed of metal grains having a graindiameter smaller than that of metal grains configuring upper layerregions 542, 543.

Subsequently, upper plating layer 532 is formed on a surface of lowerplating layer 530, and upper plating layer 533 is formed on a surface oflower plating layer 531. Upper plating layers 532, 533 include, forexample, at least one selected from Cu, Ni, Sn, Ag, Pd, Ag—Pd alloy, Au,and the like, and are each formed of a single layer or a plurality oflayers. Preferably, upper plating layer 532, 533 are formed of a Niplating layer and a Sn plating layer formed on the Ni plating layer, andare thus each formed of two layers. Thus, external electrodes 526 and527 are formed as shown in FIG. 27.

Multilayer ceramic capacitors 510 and 510′ shown in FIG. 16 or 23 arethus manufactured.

C. Exemplary Experiment

Hereinafter, an exemplary experiment of the present invention will bedescribed in detail. The present exemplary experiment does not limit thepresent invention.

According to the above-described manufacturing method, a multilayerceramic capacitor was manufactured as a multilayer ceramic electroniccomponent, and after the lower plating layer was formed, an appearanceinspection was conducted to confirm continuity and furthermore, afterthe upper plating layer was formed, a thermal shock cycle test wasconducted for evaluation.

1. Sample in Exemplary Experiment

For the exemplary experiment, Sample Nos. 1 to 24 were prepared. Eachsample was prepared by varying metal grains of the lower layer region ofthe lower plating layer and those of the upper layer region of the lowerplating layer in grain diameter and varying the thickness of the lowerand upper layer regions. Each sample was structured to be such amultilayer ceramic capacitor as shown in FIG. 1.

A multilayer ceramic capacitor having the FIG. 1 structure and thefollowing specifications was manufactured in the manufacturing methodaccording to the above-described preferred embodiment.

-   -   Dimensions of multilayer ceramic capacitor: L×W×T=about 0.6        mm×about 0.3 mm×about 0.08 mm    -   Main component of material of ceramic layer: BaTiO₃    -   Material of internal electrode layer: Ni    -   Structure of external electrode

Underlying electrode layer: An underlying electrode layer containing aNi/Cr alloy as a main component was formed by sputtering. As shown inFIG. 4, the underlying electrode layer was formed on the multilayer bodyat a portion of the first major surface and a portion of the secondmajor surface, and a corner, and the underlying electrode layer was notformed on the first and second end surfaces.

Structure of Plating Layer

Lower plating layer: Cu plating was applied.

The lower plating layer was formed on the underlying electrode layer atthe first and second end surfaces.

Thickness of lower layer region: ranging from about 0.1 μm to about 6.0μm.

Grain diameter of metal grains constituting lower layer region: rangingfrom about 0.05 μm to about 2.0 μm.

Thickness of upper layer region: ranging from about 1.0 μm to about 10μm.

Grain diameter of metal grains constituting upper layer region: rangingfrom about 0.2 μm to about 2.0 μm.

Upper plating layer: formed of a Ni plating layer and a Sn platinglayer, as seen at the multilayer body, for a total of two layers.

2. Evaluation Method (1) Confirmation of Continuity of Lower PlatingLayer

After the lower plating layer was formed the appearance inspection wasconducted to confirm continuity, as follows: After the lower platinglayer was formed, the first and second end surfaces were observed with amicroscope, and when the lower plating layer was discontinuous and theceramic layer or the internal electrode was exposed, an evaluation of NGwas made. For each sample number, 100 samples were inspected, and anysample determined as being discontinuous was counted to calculate adefect rate.

(2) Thermal Shock Cycle Test

The thermal shock cycle test was conducted as follows: after the upperplating layer was formed, solder reflow mounting was performed on apredetermined substrate for evaluation, and a bath temperature waschanged between about −55° C. and about 85° C. at an interval of about30 minutes. A change from about −55° C. to about 85° C. was regarded asone cycle, and after it was performed by 200 cycles, each sample waspolished in the LT direction for each substrate to expose a crosssection. The exposed cross section was observed with a microscope, and acracked multilayer body was evaluated as NG. For each sample number, 100samples were tested, and any sample determined as being cracked wascounted to calculate a defect rate. A sample having a defect rate of 5%or less was determined to be good.

3. Results of Experiment

Results of the above experiment are shown in Tables 1 and 2.

TABLE 1 sample no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 dimension L of(μm) 600 600 600 600 600 600 600 600 600 600 600 600 600 600 600 600multilayer ceramic capacitor dimension W of (μm) 300 300 300 300 300 300300 300 300 300 300 300 300 300 300 300 multilayer ceramic capacitordimension T of (μm) 57 57 57 57 57 57 57 57 57 57 57 57 57 57 49 57multilayer body thickness of lower (μm) 0.1 0.2 0.5 0.5 0.5 0.5 1 1 1 21.5 2 4 6 1 1 layer region thickness of upper (μm) 4 4 4 4 4 4 4 4 4 4 11 2 2 8 10 layer region grain diameter of (μm) 0.05 0.05 0.05 0.1 0.20.5 0.2 0.5 1 2 0.5 0.5 1 2 0.2 0.2 metal grains of lower layer regiongrain diameter of (μm) 2 2 2 2 2 2 2 2 0.5 0.5 0.5 0.5 1 0.5 2 2 metalgrains of upper layer region defect rate (%) 0.0 0.0 0.0 0.0 0.0 2.0 0.02.0 10.0 16.0 7.0 9.0 20.0 61.0 0.0 5.0 through thermal impact cycletest defect rate as a (%) 70.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 57.044.0 0.0 0.0 0.0 0.0 result of confirming continuity of lower platinglayer

TABLE 2 sample no. 17 18 19 20 21 22 23 24 dimension L of multilayer(μm) 600 600 600 600 600 600 600 600 ceramic capacitor dimension W ofmultilayer (μm) 300 300 300 300 300 300 300 300 ceramic capacitordimension T of multilayer body (μm) 57 57 57 57 57 57 57 57 thickness oflower layer region (μm) 1 1 1.5 0.5 0.5 0.5 1 1 thickness of upper layerregion (μm) 4 1 1 4 4 4 4 2 grain diameter of metal grains (μm) 0.2 0.20.2 0.2 0.2 0.2 0.1 0.1 of lower layer region grain diameter of metalgrains (μm) 0.5 0.5 0.5 1.5 1 0.5 0.2 0.2 of upper layer region defectrate through thermal impact (%) 0.0 0.0 3.0 0.0 0.0 0.0 0.0 2.0 cycletest defect rate as a result of confirming (%) 0.0 70.0 0.0 0.0 0.0 0.010.0 44.0 continuity of lower plating layer

Initially, a result of focusing on a relationship between a graindiameter of metal grains of the lower layer region and a grain diameterof metal grains of the upper layer region will be described.

The samples of Sample Nos. 1 to 8 and Sample Nos. 15 to 24, with a lowerlayer region with metal grains having a grain diameter smaller than thatof metal grains of an upper layer region, presented good results in thethermal shock cycle test.

When the samples of Sample Nos. 3 to 6 and those of Sample Nos. 20 to 24(all having a lower layer region with a thickness of about 0.5 μm) werecompared, the samples of Sample Nos. 3 to 5 had a lower layer regionwith metal grains having a grain diameter of about 0.2 μm or less, andas a result of the thermal shock cycle test, presented any result incontinuity of the lower plating layer satisfactorily. Further, SampleNos. 20 to 22 had an upper layer region with metal grains having a graindiameter of about 0.5 μm or more, and as a result of the thermal shockcycle test, presented any result in continuity of the lower platinglayer satisfactorily. Sample Nos. 6 and 8 had a lower layer region withmetal grains having a grain diameter of about 0.5 μm, and accordingly,as a result of the thermal shock cycle test, presented a defect rate ofabout 2.0%.

In contrast, the samples of Sample Nos. 9 to 14 had a lower layer regionwith metal grains having a grain diameter equal to or larger than thatof metal grains of an upper layer region, and as a result of the thermalshock cycle test, all presented a result of about 7% or more and werethus defective.

A result of focusing on a relationship between the thickness of thelower layer region and the thickness of the upper layer region will bedescribed.

The samples of Sample Nos. 1 to 8, 17 and 20 to 24, with a lower layerregion having a smaller than an upper layer region, presented goodresults in the thermal shock cycle test.

Further, Sample Nos. 2 to 5, 7, 15, 17, and 20 to 22 had a lower layerregion with metal grains having a grain diameter smaller than that ofmetal grains of an upper layer region and had a thickness of about 0.2μm or more and about 1.0 μm or less, and an upper layer region which hada thickness of about 4.0 μm or more and about 8.0 μm or less, andaccordingly, as a result of the thermal shock cycle test, presented anyresult in continuity of the lower plating layer satisfactorily. Incontrast, Sample No. 1 had a lower layer region with a thickness ofabout 0.1 μm, and accordingly, presented a good result in the thermalshock cycle test, although the sample had a lower plating layerpresenting a high defect rate of about 70% in continuity as a result.Sample No. 16 had an upper layer region with a thickness of about 10 μm,and accordingly, as a result of the thermal shock cycle test, presenteda defect rate of about 5.0%.

Further, when Sample Nos. 5, 7 and 17 to 19 (all having a lower layerregion composed of metal grains having a grain diameter of about 0.2 μm)were compared, the samples of Sample Nos. 5, 7 and 17 had a lower layerregion with a smaller thickness than an upper layer region, and as aresult of the thermal shock cycle test, presented any result incontinuity of the lower plating layer satisfactorily. In contrast, thesamples of Sample No. 18 had a lower layer region have an equal orsubstantially equal to an upper layer region, and accordingly, presenteda good result in the thermal shock cycle test, although the samples hada lower plating layer presenting a high defect rate of about 70% incontinuity as a result, and the samples of Sample No. 19 had a lowerlayer region with a larger thickness than an upper layer region, andaccordingly, as a result of the thermal shock cycle test, presented adefect rate of about 3.0%.

Thus, those samples of each sample number which have a lower layerregion with metal grains having a grain diameter smaller than that ofmetal grains of an upper layer region ensure adhesion with a multilayerbody by an underlying electrode layer defined by a thin film layer, andcan reduce compressive stress throughout a lower plating layer as thelower layer region includes metal grains having the smaller graindiameter. As a result, it has been confirmed that even when thermalstress is applied, tensile stress applied to a peripheral portion of thelower plating layer can be reduced or prevented, and cracking of themultilayer body due to the thermal stress can be reduced or prevented.

For example, while in the above-described preferred embodiments and eachexemplary variation thereof, only examples having a symmetrical orsubstantially symmetrical shape in front view are illustrated, themultilayer ceramic electronic component according to preferredembodiments of the present invention can have an external shape changedvariously depending on to what it is mounted and required performance.Further, the present invention also includes a combination of all orsome of the above-described preferred embodiments and each exemplaryvariation thereof, as appropriate.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A multilayer ceramic electronic componentcomprising: a multilayer body including a plurality of stacked ceramiclayers and including a first major surface and a second major surfaceopposite to each other in a height direction, a first side surface and asecond side surface opposite to each other in a width directionorthogonal or substantially orthogonal to the height direction, and afirst end surface and a second end surface opposite to each other in alength direction orthogonal or substantially orthogonal to the heightdirection and the width direction; a first internal electrode layer onat least one of the plurality of stacked ceramic layers and exposed atthe first end surface; a second internal electrode layer on at least oneof the plurality of ceramic layers and exposed at the second endsurface; a first external electrode connected to the first internalelectrode layer and located on the first end surface; and a secondexternal electrode connected to the second internal electrode layer andlocated on the second end surface; wherein the first and second externalelectrodes includes an underlying electrode layer, a lower plating layeron the underlying electrode layer at the first end surface and thesecond end surface, respectively, and an upper plating layer on thelower plating layer; the underlying electrode layer includes a thin filmelectrode including at least one selected from Ni, Cr, Cu, and Ti; thelower plating layer is a Cu plating layer; the lower plating layerincludes a lower layer region located closer to the multilayer body andan upper layer region located between the lower layer region and theupper plating layer; the Cu plating layer in the lower layer region hasa metal grain diameter smaller than that of the Cu plating layer in theupper layer region.
 2. The multilayer ceramic electronic componentaccording to claim 1, wherein the Cu plating layer in the lower layerregion has a metal grain diameter of about 0.20 μm or less, and the Cuplating layer in the upper layer region has a metal grain diameter ofabout 0.5 μm or more.
 3. The multilayer ceramic electronic componentaccording to claim 1, wherein the lower layer region is smaller inthickness than the upper layer region.
 4. The multilayer ceramicelectronic component according to claim 1, wherein the lower layerregion has a thickness of about 0.2 μm or more and about 1.0 μm or less,and the upper layer region has a thickness of about 4.0 μm or more and8.0 μm or less.
 5. A multilayer ceramic electronic component comprising:a multilayer body including a plurality of stacked ceramic layers and aplurality of internal electrode layers, and including a first majorsurface and a second major surface opposite to each other in a heightdirection, a first side surface and a second side surface opposite toeach other in a width direction orthogonal or substantially orthogonalto the height direction, and a third side surface and a fourth sidesurface opposite to each other in a length direction orthogonal orsubstantially orthogonal to the height direction and the widthdirection; and a plurality of external electrodes on the side surfacesof the multilayer body; wherein the plurality of internal electrodelayers include a plurality of first internal electrode layers and aplurality of second internal electrode layers, with the first and secondinternal electrode layers alternately stacked with the ceramic layerinterposed therebetween; the first internal electrode layer includes afirst lead electrode portion extending to one of the first, second,third and fourth side surfaces, and a second lead electrode portionextending to one side surface other than the side surface to which thefirst lead electrode portion extends; the second internal electrodelayer include a third lead electrode portion extending to one of thefirst, second, third and fourth side surfaces, and a fourth leadelectrode portion extending to one side surface other than the sidesurface to which the third lead electrode portion extends; the pluralityof external electrodes include a first external electrode connected tothe first lead electrode portion, a second external electrode connectedto the second lead electrode portion, a third external electrodeconnected to the third lead electrode portion, and a fourth externalelectrode connected to the fourth lead electrode portion; the first,second, third and fourth external electrodes include an underlyingelectrode layer, a lower plating layer on the underlying electrode layerat the third side surface and the fourth side surface, and an upperplating layer on the lower plating layer; the underlying electrode layerincludes a thin film electrode including at least one selected from Ni,Cr, Cu, and Ti; the lower plating layer is a Cu plating layer; the lowerplating layer includes a lower layer region located closer to themultilayer body and an upper layer region located between the lowerlayer region and the upper plating layer; and the Cu plating layer inthe lower layer region has a metal grain diameter smaller than that ofthe Cu plating layer located in the upper layer region.
 6. Themultilayer ceramic electronic component according to claim 5, whereinthe Cu plating layer in the lower layer region has a metal graindiameter of about 0.20 μm or less, and the Cu plating layer in the upperlayer region has a metal grain diameter of about 0.5 μm or more.
 7. Themultilayer ceramic electronic component according to claim 5, whereinthe lower layer region is smaller in thickness than the upper layerregion.
 8. The multilayer ceramic electronic component according toclaim 5, wherein the lower layer region has a thickness of about 0.2 μmor more and about 1.0 μm or less, and the upper layer region has athickness of about 4.0 μm or more and 8.0 μm or less.
 9. The multilayerceramic electronic component according to claim 1, wherein each of theplurality of stacked ceramic layers has a thickness of about 0.4 μm ormore and about 10 μm or less.
 10. The multilayer ceramic electroniccomponent according to claim 1, wherein each of the plurality of stackedceramic layers includes at least one of BaTiO₃, CaTiO₃, SrTiO₃, orCaZnO₃ as a main component.
 11. The multilayer ceramic electroniccomponent according to claim 10, wherein each of the plurality ofstacked ceramic layers further includes at least one of an Mn compound,an Fe compound, a Cr compound, a Co compound, or a Ni compound as asub-component.
 12. The multilayer ceramic electronic component accordingto claim 1, wherein each of the first and second internal electrodelayers has a thickness of about 0.2 μm or more and about 2.0 μm or less.13. The multilayer ceramic electronic component according to claim 1,further comprising an upper plating layer covering the lower platinglayer.
 14. The multilayer ceramic electronic component according toclaim 13, wherein the upper plating layer includes at least one of Ni,Sn, Cu, Ag, Pd, Ag—Pd alloy, or Au.
 15. The multilayer ceramicelectronic component according to claim 5, wherein each of the pluralityof stacked ceramic layers has a thickness of about 0.4 μm or more andabout 10 μm or less.
 16. The multilayer ceramic electronic componentaccording to claim 5, wherein each of the plurality of stacked ceramiclayers includes at least one of BaTiO₃, CaTiO₃, SrTiO₃, or CaZnO₃ as amain component.
 17. The multilayer ceramic electronic componentaccording to claim 16, wherein each of the plurality of stacked ceramiclayers further includes at least one of an Mn compound, an Fe compound,a Cr compound, a Co compound, or a Ni compound as a sub-component. 18.The multilayer ceramic electronic component according to claim 1,wherein each of the plurality of internal electrode layers has athickness of about 0.2 μm or more and about 2.0 μm or less.
 19. Themultilayer ceramic electronic component according to claim 5, furthercomprising an upper plating layer covering the lower plating layer. 20.The multilayer ceramic electronic component according to claim 19,wherein the upper plating layer includes at least one of Ni, Sn, Cu, Ag,Pd, Ag—Pd alloy, or Au.